阅读说明：本技术 用于增材制造的物体模型中的嵌套分段 (Nested segmentation in object models for additive manufacturing ) 是由 摩根·T·施拉姆 马修·A·谢泼德 贾克·赖特 赫克托·勒布龙 程昕 瓦内沙·韦尔兹韦尔特 于 2017-07-10 设计创作，主要内容包括：在示例中,一种方法包括：在处理器处接收在增材制造中要被生成的物体的数据模型。包括物体的至少一部分的表示的虚拟构造体积可被分割成包括核心分段和外围分段的多个嵌套分段。分割虚拟构造体积可包括基于物体的几何形状和预期的物体属性的至少一个来确定外围分段的尺寸。(In an example, a method includes: a data model of an object to be generated in additive manufacturing is received at a processor. A virtual construction volume including a representation of at least a portion of an object may be segmented into a plurality of nested segments including a core segment and a peripheral segment. Segmenting the virtual build volume may include determining a size of the peripheral segment based on at least one of a geometry of the object and an expected property of the object.)

1. A method, comprising:

receiving, at a processor, a data model of an object to be generated in additive manufacturing; and

segmenting, by the processor, a virtual construction volume comprising a representation of at least a portion of the object, wherein the virtual construction volume is segmented into a plurality of nested segments comprising a core segment and a peripheral segment, and wherein the segmenting comprises determining a size of the peripheral segment based on at least one of a geometry of the object and an expected object property.

2. The method of claim 1, comprising: segmenting the virtual build volume such that the peripheral segment has a variable thickness.

3. The method of claim 2, comprising segmenting the build volume into the plurality of segments such that there is a first ratio of a thickness of the inner segment relative to a thickness of the outer segment at a location of a first object feature and a second ratio of the thickness of the inner segment relative to the thickness of the outer segment at a location of a second object feature, the second object feature being larger than the first object feature, wherein the second ratio is smaller than the first ratio.

4. The method of claim 1, comprising determining peripheral segments outside the representation of the object within the virtual construction volume.

5. The method of claim 1, comprising determining a size of a peripheral segment of an object region based on a location of the object region in the object.

6. The method of claim 5, comprising determining at least one peripheral segment to have a variable thickness, wherein the thickness of the peripheral segment of a first object region comprising a surface of the object having a first orientation is different from the thickness of the segment of a second object region comprising a surface of the object having a second orientation.

7. The method of claim 1, further comprising generating additive manufacturing control instructions from the nested segments, wherein the additive manufacturing control instructions for each segment are generated using different processing parameters.

8. The method of claim 7, further comprising generating an object using additive manufacturing based on the control instructions.

9. An apparatus comprising processing circuitry, the processing circuitry comprising:

an object segmentation module to represent a virtual construction volume comprising at least a portion of an object to be generated in additive manufacturing as a plurality of nested segments comprising a peripheral segment and an object core segment; and

a model evaluation module for determining a relative volumetric composition of the segments from data relating to the object,

wherein the object segmentation module is to determine a shape of the peripheral segment based on the determination by the model evaluation module.

10. The apparatus of claim 9, wherein the model evaluation module is to determine a plurality of local relative volumetric compositions for the segment within the object based on a local geometry of the object and at least one expected object property.

11. The apparatus of claim 9, wherein the processing circuit further comprises: a control instruction module to generate a control instruction for generating an object, wherein the generation of the control instruction by the control instruction module uses different processing parameters for different segments.

12. The apparatus of claim 11, further comprising object generation means for generating the object in accordance with the control instruction.

13. A machine-readable medium storing instructions that, when executed by a processor, cause the processor to:

a data model of a virtual construction volume comprising at least a part of an object to be generated in a three-dimensional object generation is segmented into at least one peripheral segment arranged around a core segment, wherein the at least one peripheral segment has a variable thickness.

14. The machine-readable medium of claim 13, further storing instructions that, when executed by a processor, cause the processor to segment the data model to have a thickness of the peripheral segment in an object region based on at least one of:

a local size of the object;

local direction of object features;

a vertical position of the object region within the object in a manufacturing direction; and

the expected object properties.

15. The machine-readable medium of claim 13, further storing instructions that, when executed by a processor, cause the processor to:

control instructions for generating the object are determined by applying the first processing parameter to the first segment and applying the second processing parameter to the second segment.

Background

Three-dimensional (3D) printing is an additive manufacturing process in which three-dimensional objects may be formed, for example, by selective curing of successive layers of build material. The object to be formed may be described in a data model. Selective curing may be achieved, for example, by melting, bonding, or curing by processes including sintering, extrusion, and irradiation. The quality, appearance, strength, and functionality of objects produced by such systems may vary depending on the type of additive manufacturing technique used.

Drawings

Non-limiting examples will now be described with reference to the accompanying drawings, in which:

FIG. 1 is an example of a method for generating a segmented data model for an object to be generated in additive manufacturing;

FIGS. 2A, 2B, and 2C illustrate examples of a segmentation model;

FIG. 3 is an example of a method of generating an object;

fig. 4 and 5 are examples of an apparatus for processing data relating to additive manufacturing; and

FIG. 6 is an example of a machine-readable medium associated with a processor.

Detailed Description

Additive manufacturing techniques may generate three-dimensional objects through solidification of build material. In some examples, the build material may be a powdered particulate material, which may be, for example, a plastic, ceramic, or metal powder. The properties of the generated object may depend on the type of build material and the type of curing mechanism used. Build material may be deposited on, for example, a print bed, and processed layer-by-layer within, for example, a fabrication chamber.

In some examples, selective curing is achieved by directionally applying energy, for example using a laser or electron beam, which results in curing of the build material with the application of the directional energy. In other examples, at least one marking agent may be selectively applied to the build material and may be a liquid when applied. For example, a fixer (also referred to as a "coalescing agent" or "coalescing agent") may be selectively distributed onto portions of a layer of build material in a pattern derived from data representing a slice of a three-dimensional object to be generated (which may be generated, for example, from structural design data). The fixer may have a composition that absorbs energy such that when energy (e.g., heat) is applied to the layers, the build material coalesces and solidifies according to the pattern to form a slice of the three-dimensional object. In other examples, coalescing may be achieved in some other manner.

Another example of a printing agent is a coalescence modifier agent (which may be referred to as a modifier or a refiner), which functions to alter the effect of the fixer and/or applied energy, or to help create a particular surface or appearance for an object, for example, by inhibiting, reducing, or increasing coalescence. For example, property modifiers including dyes, colorants, conductive agents, agents for providing transparency or elasticity, and the like, may be used in some examples as fixatives or modifiers and/or as printing agents for providing specific properties to objects.

The additive manufacturing system may generate an object based on the structural design data. This may involve the designer generating a three-dimensional model of the object to be generated, for example, using a computer-aided design (CAD) application. The model may define a solid portion of the object. To generate a three-dimensional object from a model using an additive manufacturing system, model data may be processed to generate parallel-planar slices of the model. Each slice may define at least a portion of a respective layer of build material that will be solidified or caused to coalesce by the additive manufacturing system.

Fig. 1 illustrates an example of a method, which may be a computer-implemented method, such as a method implemented using at least one processor, and which may include a method of generating a segmented data model for an object to be generated in additive manufacturing. These segments may, for example, represent nested "shells" of objects to be generated and/or surrounding regions that may be generated using different processing parameters. In some examples, the segments may, for example, represent portions of the object that are to be generated using a particular combination and/or amount of printing agent, thereby having different properties, such as different colors, or different mechanical or functional properties. For example, a particular desired color may be provided by an outer shell having a first color, an inner shell having a different color, and a core of a third color.

Block 102 includes receiving, at a processor, a data model of an object to be generated in additive manufacturing. The data model may be received, for example, from memory, over a network, over a communication link, etc., and may model all or part of the object. In some examples, the data model may include object model data and object property data, for example. The object model data may define a three-dimensional geometric model of at least a portion of the model object, including the shape and extent of all or part of the object in a three-dimensional coordinate system, such as a solid portion of the object. In some examples, the data model may represent the surface of the object as, for example, a mesh. The object model data may be generated, for example, by a Computer Aided Design (CAD) application. The object property data may define at least one object property for the three-dimensional object to be generated or for a part of the three-dimensional object to be generated. If no object property data exists, the object may have certain default properties based on the build material and printing agent used. In one example, the object property data may include any one or any combination of color, flexibility, elasticity, stiffness, surface roughness, porosity, interlayer strength, density, transparency, conductivity, etc. of at least a portion of the object to be generated. The object property data may define a plurality of object properties for one or more portions of the object, and the specified properties may vary from object to object.

Block 104 includes segmenting, by a processor, a virtual build volume (virtual build volume) including at least a portion of an object (or a representation thereof) into a plurality of nested segments including a core segment and at least one peripheral segment. Determining the segments includes determining dimensions of the peripheral segments, and may be based on at least one of a geometry of the object and an expected object property (e.g., color, intensity, resiliency, etc.).

The virtual build volume may, for example, include a bounding box that encloses the object, may be the size and shape of the object (i.e., follows the surface of the object), and/or represent at least a portion of the build volume in which the object is to be fabricated. In some examples, the virtual build volume may include one or more "slices," each of which may represent a layer of the object to be fabricated in layer-by-layer additive manufacturing of the object, and/or at least a portion of a manufacturing chamber in which the object is to be fabricated.

In some examples, a plurality of nested peripheral segments may be generated, as described in more detail below. Such segments may be internal peripheral segments or peripheral to the core.

The nesting of segments may be complete or partial (i.e., the peripheral segments may extend around the entire boundary of the core segment or the inner peripheral segment, or only a portion of the boundary). In some examples, the at least one peripheral segment may form a shell around the core segment. The core may comprise any inner segment having a peripheral segment formed around at least a portion of the inner segment.

In some examples, the determined dimensions of the peripheral segment include a thickness (which may be a two-dimensional thickness or a three-dimensional thickness) of at least one peripheral segment of the core segment surrounding the object. As set forth further below, in some examples, the thickness of such peripheral segments may vary depending on local geometry and/or locally expected object properties.

The segments may be processed separately when determining instructions for generating the object. For example, different mapping resources or rules may be applied to different segments.

Differentiating between segments can have a variety of uses in additive manufacturing. For example, when printing 3D colored objects, a trade-off may be made between the desired color of the object and the mechanical properties of the object. When a large amount of thermal energy is applied to the build material to fuse the layers together, a higher density 3D object with significant mechanical strength and functionality can be generated. The amount of thermal energy available for fusing depends in part on the intensity of the radiation absorbed by the fixer, and the radiation absorptivity of the fixer depends in part on the color of the fixer. For example, near infrared fixatives with cyan, magenta, or yellow (C, M or Y) colorants typically have lower absorption strengths than, for example, carbon black-based fixatives, which are effective energy absorbers. Thus, the fusion grade of any build material to which the colorant is applied is lower than that of a similarly produced 3D printed black object, which can result in a colored object having lower density and less mechanical strength and functionality than a comparable black object.

However, by distinguishing the segments when generating instructions for generating an object, a colored shell corresponding to the peripheral segments can be formed, for example, around a solid core to which a carbon black-based fixer is applied. This makes it possible to brighten the object without excessively impairing its strength.

While in some examples, a colored peripheral segment can be determined with respect to a core segment that is fused using a carbon black-based fixer, the color gamut of the resulting object can be reduced by the surface visibility of the underlying core segment (which may be more so for a partially transparent outer peripheral segment). Providing a thicker outer segment provides a higher degree of hiding of the color of the core, but may sacrifice strength and/or increase cost (e.g., the cost of the colorant may be higher). Providing at least one intermediate peripheral segment may allow for a more gradual transition of properties (e.g., from black to color).

Although the example of color is used here, the same is true for other attributes: for example, the object may be generated to include a relatively strong but possibly relatively brittle core. This may be protected by an outer segment which is relatively resilient, the thickness of which is determined according to the desired level of protection. By providing a number of peripheral segments (e.g. n shells), a smooth and/or gentle transition from the core to the surface may be achieved. If instead, for example, there is a brittle outer section around a strong core, it may yield in some way, resulting in a sudden load surge on the core. The weaker outer segment may yield gradually under pressure with a smooth transition through the n nested segments.

Furthermore, the overlying peripheral segment of increased elasticity toward the surface may protect the core segment from being more effectively fractured by absorbing energy while providing the desired surface elasticity as compared to a single elastic segment surrounding the core. The elasticity of such peripheral segments and their thickness can thus be determined on a segment-by-segment basis.

In some examples, the segment thickness may be sacrificed, e.g., to allow another segment to occupy a greater proportion of the volume. For example, the width of the outer peripheral segment may be reduced to allow the inner segment (which may be the core segment or the inner peripheral segment) to have a particular strength, heat of fusion, have a threshold size, and so on.

In examples where the dimensions (e.g., thickness) are determined based on the geometry of the object, this may include determining a local feature size, such as a cross-sectional area of the object at a location. In another example, determining the thickness based on the geometry of the object may include determining a location of a segment (or a portion of a segment) within the object: for example, the upper portions of the object (those portions later formed during manufacturing) may be associated with a different segment thickness than the lower portions, and/or the upwardly facing face may be associated with a different segment thickness than the downwardly facing face, which may take into account thermal considerations during manufacturing, etc.

In examples where the dimensions are determined based on object properties (which may vary from object to object and/or internally), this may include determining the dimensions based on a property threshold, an expected property gradient (e.g., a conductivity gradient, a resilience versus stiffness gradient, etc.), and/or a quality indicator.

To take into account the example of property thresholds, an object may have two or more properties, and applying a print agent uniformly across the object may be difficult to achieve. For example, there may be a threshold intensity and a specified color. Indeed, as described above, in some examples, colored objects may be relatively weak. Thus, in some examples, the threshold intensity may be provided by the core portion, while the color may be provided by the peripheral segment. The thickness of the peripheral segment may be determined so as to provide a core for providing at least a threshold intensity and/or so as to provide a threshold color quality (e.g., brightness). In some examples, a combination of qualities may not be provided given the available materials or given object geometry, etc. (e.g., it may be difficult or impossible to provide high strength with high elasticity, or high strength and vivid color). In such an example, the first segment may be designated to provide one of the attributes (e.g., according to a predetermined hierarchy) and the other attribute may be matched as closely as possible given the constraint.

In another example, attributes such as color may be specified and segments may be determined to provide color in as thin segments as possible, as colored print agents may be associated with higher costs. This may vary, for example, based on the lightness of the color and/or the transparency of the material, etc.

To take into account an example of a quality indicator, a segment, which may be an outer segment, may be associated with a processing parameter intended to provide a bright color, which may be provided at the expense of object intensity (e.g., the ratio of colorant to fixer may be higher than in other portions). Such segmentation may be specified as being relatively thick when segmenting a model of an object associated with a high color quality indicator. However, when a lower color quality is acceptable, the segment may be specified, but the segment is relatively thin. The reverse may be true for the intensity indicator, i.e., a high intensity indicator may be associated with a thin color segment (because, as described above, color segments may tend to be weak in some examples). In another example, the segments may be determined to provide a threshold parameter in a particular first attribute (e.g., intensity), and the remaining segments may be determined to optimize a second attribute (e.g., color), for example, given the constraints of the first parameter.

To account for the property gradient, each segment may be associated with a phase in the varying property parameter. For example, the outer segment may have a high elasticity, and the middle segment may have a medium elasticity, and the core may have a relatively low elasticity (which in some examples is relatively brittle). In another example, the outer segments may be bright colors, the middle segments may have a middle color, and the core may have a relatively dark color. In such examples, the relative thickness of the segments may determine the appearance and/or functional behavior of the object, such as a threshold force or brightness of the outer segments causing permanent damage thereto. The thickness of the segments may be selected accordingly.

The segmentation may be determined for the entire object (or for a build volume containing the entire object), or may be determined for the or each "slice" of the build volume/object, which may correspond to a layer of build material to be processed in a layer-by-layer additive manufacturing process to generate a layer of the object.

Fig. 2A shows an example of a representation of a 3D object 200, in which the 3D object 200 is spherical, segmented into segments. In this example, there is a core segment 202 surrounded by two concentric shell-like peripheral segments 204 and 206. The thickness of the peripheral segments 204 and 206 may be determined according to the method of block 104 above. For purposes of discussion, the object 200 may be considered to be represented in a manner similar to a "geomodel," having a core (core segment 202), a mantel (inner shell 204), and an outer shell (outer shell 206).

In an example of the method of fig. 1, the data model received in block 102 may be a spherical model, and the segments 202, 204, 206 may be determined in block 104.

Although in this example, the core segment 202 is located substantially in the center of the object 200, this is not the case in all examples. In addition, although in this example the peripheral segments 204 and 206 are concentric and their boundaries follow the contour of the surface of the object 200, in other examples they lack one or both of these properties. Indeed, in some examples, there may be multiple object core segments 202 around which the peripheral segments 204 and 206 are formed.

Fig. 2B shows a representation of a slice 208 of the object to be generated. In this example, the object comprises an elongated structure having a narrow central portion 210 and two wider end portions 212a, 212 b. In this example, the core segment 214 extends toward either end of the object via the central portion 210. At either end, two peripheral segments 216, 218 are formed, but when the outer peripheral segment 218 extends through the central portion 210, the inner peripheral segment 216 is absent (i.e., in one manner, it can be considered to have zero thickness at the central portion). Further, in this example, the thickness of the outer peripheral segment 218 is reduced in the relatively narrower central portion 210, thereby allowing the width of the core segment 214 to be increased.

Thus, in some examples, as shown in the example of fig. 2B, determining the segment in block 104 may include segmenting the model received in block 102 (in this example, the model of slice 208) into at least one peripheral segment having a variable thickness (i.e., thicker at some points than at other points), and determining a peripheral segment having a non-zero thickness in the first object region and a zero thickness in the second object region.

In this example, another peripheral segment 220 is formed on the exterior of the object. To continue with the example of the geological model above, this peripheral segment 220 may be considered to comprise the "atmosphere" of the object. In other words, in some examples, determining the peripheral segment in block 104 may include determining at least one segment outside of the object. As described further below, the segmentation may be used to define printing instructions that may provide thermal control or to enhance object properties.

In fig. 2C, peripheral section 222 is wider in first region 224 than in second region 226 (and core section 228 is correspondingly narrower in first region 224 than in second region 226. this may allow for properties to be different in different regions 224, 226. for example, if peripheral section 222 is to be processed to provide a colored outer shell and the core is to be processed to provide strength (e.g., including a high proportion of "carbon black" fixer), there may be a different tradeoff between the thicknesses of the first and second regions-since first region 224 has a thicker peripheral section 222, first region 224 may be more vibrant than second region 226, while the color of the second region may be dictated by the color of core section 228 (which may be formed of carbon black, and thus relatively darker, even if overlapping but relatively thin peripheral sections are formed), the second region 226 may be relatively strong because, as described above, the colored portions may have a lower intensity due to their generally lower ability to absorb radiation.

In case the slice of the object is formed into segments, this may be performed independently for the different segments. For example, the core segments in one slice may be aligned, partially aligned, or non-overlapping with the core segments in a previous or subsequent slice. Different slices may have different numbers of segments.

In some examples, the thickness of the peripheral segments may determine the rate of change of the characteristic, and by selecting the thickness (or size) of each peripheral segment accordingly, greater control over the characteristic may be obtained. In some examples, the thickness of the one or more peripheral segments may allow for control of the trade-off between the appearance and mechanical properties. The thickness of the peripheral segment may also be set to allow another peripheral segment (e.g., a core segment or an inner peripheral segment that provides strength) to be provided, for example, of a threshold size or volume ratio.

In some examples, a low-tone fixer may be used in place of carbon black, relative to at least some of the segmentations, which may increase the color gamut available for the object. However, if such an alternative fixer is a less efficient endothermic agent and/or is more expensive (either by itself or by applying more agent or energy to reach the fixing temperature), its use may be controlled so that it is used only in those cases that provide particular benefits (e.g., vivid color). For example, its use may be limited to peripheral segments (e.g., outer peripheral segments) where the end user can see the color.

For example, a lower slice of the object (to be formed as an initial layer of the object, i.e., manufactured first in a layer-by-layer manufacturing process) may be divided such that a higher amount of fixer (or fixer associated with a more efficient energy absorption rate, such as carbon black) may be applied thereto than may be applied to an upper layer, which may absorb heat from the previous layer. In another example, due to the nature of additive manufacturing, the color of the face of an object may depend on the spatial orientation of the face. Thus, the segments may be formed based at least in part on the orientation of at least a portion of the face of the object affected by the segments.

Thus, in some examples, defining segments allows each segment to be processed to provide different characteristics: for example, the core may be treated to provide high density and high mechanical strength, and may be surrounded by an outer shell structure having a lower density but high quality vivid color. The intermediate peripheral segments may mask or reduce the effect of dark cores on such bright outer peripheral segments. Each segment within the object may be processed using different 3D printing process parameters selected to achieve the desired characteristics of the segment. The processing parameters may allow for the selection of predetermined reagents and/or amounts or ratios of such reagents. In other examples, the mode of application of the agent may vary between layers. For example, the agent clustering may be varied to provide or enhance certain attributes.

In some examples, the processing parameters associated with the segments may specify the accessible print agents, print agent combinations, and/or amounts of print agents, and may differ between segments. In some examples, the processing parameters may be saved in the form of mapping resources, such as look-up tables, or mapping algorithms for identifying the amount and/or combination of printing agents applied to the object regions corresponding to particular object segments, with different or modified mapping resources associated with different segments.

As described above, in some examples, the size of nested peripheral segments may vary, allowing greater versatility in additive manufacturing, for example, providing a greater range of object properties and functions. For example, the visual requirements of color may vary with the object: portions of the object that are less likely to be visible in normal use, or relatively small or geometrically complex portions (the human eye is relatively less sensitive to color variations in such regions) may be printed at lower quality standards applied to the color without sacrificing the perceived color quality of the object. Thus, the peripheral segments may be thinner in these portions and the use of color print agent may be less than if such segments were thicker. In another example, a bottom portion of an object may have a different dimensional tolerance or strength property than a top portion of the portion. In such an object part, the volume of the core segment may be increased. Since the fine features may be weaker than the portion with the larger cross-section, any core may, for example, constitute a relatively large portion of the cross-sectional area of the object at this point (although, as noted above, it may, for example, sacrifice color, this may be less important for smaller areas). In addition, this may allow for different thermal properties during the fusing process depending on the location of the object. For example, the initial layers (i.e., those layers formed earlier in additive manufacturing) may be provided with a higher amount of fixer (or more effective fixer) than the upper layers, which may absorb heat from the previous layers, by specifying a larger core or internal segment for such layers.

As described above, in some examples, at least one peripheral segment may be external to the object model, including an "atmospheric" segment. This may for example be used to control the extent of application of the refiner on the object. Since it is possible to consider reducing the heat of such a reagent, it is possible to adjust according to the heat that may be generated in the location part of the object: in general, a portion of the object having a smaller cross-section may generate less heat than a portion of the object having a larger cross-section. In some examples, build material from outside the object may adhere to the surface of the object, which may reduce the appearance quality of the object. This may occur, for example, when unfused or partially fused build materials having a white appearance adhere to an object surface. Thus, in some examples, a color may be added to a portion of the build material corresponding to the outer segment to match the color of the generated object. In other words, since some of the build material to which the atmospheric color is applied may adhere to the object, the color may be applied to content that is expected to be outside the object being generated. Also, as described above, the color of the face of the object may depend on the spatial direction of the face. A thicker "atmospheric" segment may be designated if there are one or more outer peripheral segments that are thicker to produce the target color. For example, the upward facing surface may be designated to have thicker color containing segments and also thicker outer peripheral segments.

Since applying color to areas intended to be outside the object utilizes resources and/or may affect the recyclability of the build material, the thickness of such segments may be reduced, even to zero, in certain areas where the appearance quality may be deemed less important. In other examples, color may be used in a first outer region closer to the object, while color is omitted in a second outer region further from the object, but a cooling refiner may still be added in the second outer region: as the thickness of the first outer segment increases, the effectiveness of preventing uncolored build material from adhering to objects and the cost of resources may increase. By allowing control of the thickness of the first segment, this allows the desired quality index in a given construction operation to be met without excessive use of colorants.

Fig. 3 is an example of a method of generating an object, where blocks 302-310 are examples of methods of performing block 104 above.

In this example, the dimension to be determined is the thickness, and more specifically, the variable thickness of the peripheral section is determined.

In block 302, the geometry of the object is considered, and in this example, the local geometry of the object at each point where there may be segmentation is considered. When considering a slice of the object, this may comprise a cross-section of the slice at that point. In the case where the object as a whole is to be segmented, the size of the object features may be determined. In one example, this may include integrating the "voxel density". A voxel may describe a region of the model and is similar to a voxel. The voxels may have a consistent shape and size, in some examples cubes, which are determined such that each voxel may be individually addressed by the object generation apparatus (although such an apparatus may also be capable of applying print agent at sub-voxel resolution). In some examples, the object properties are specified at a voxel resolution.

Integrating the voxel density may include determining a number of voxels in a fixed spherical radius, e.g., containing a portion of the object model, to determine a local feature size (or a circular radius in a slice). In such an example, if there is a high percentage of voxels within the local neighborhood that are filled with objects, then the feature may be determined to be relatively large. If there are few voxels filled in this local neighborhood, small features can be identified. In other examples, the feature size may be determined in other ways, such as having been marked by a user, and so forth.

Block 304 includes determining the segmentation such that there is a first ratio of the thickness of the inner segment relative to the thickness of the outer segment at the location of a first object feature and a second ratio of the thickness of the inner segment relative to the thickness of the outer segment at the location of a second object feature, the second object feature being larger than the first object feature. Both the outer and inner segments may comprise peripheral segments or the inner segment may comprise a core. In other words, the relative volume occupied by the segments may vary depending on the size of the features. In some examples, one peripheral segment may be reduced to have zero thickness to allow for an increase in the size of the core or the like. In some examples, this may occur in the area of smaller object features (as shown in fig. 2B). In some examples, the thickness of the peripheral segment may be less in the area of the small object feature than in the area of the large object feature (which may, for example, allow the core to occupy a greater proportion and/or threshold volume of the smaller object feature).

Block 306 includes determining a location of the object region in the object, and block 308 includes determining a size of the peripheral segment within the object region based on the location of the object region in the object. For example, as described above, the location within the object may be related to an expected physical property: the lower portion or base of the object may be stronger or heavier when generated to provide an anti-toppling object, and thus, in such areas, the core may be emphasized over a peripheral segment that is relatively thin or has zero thickness. However, the upper portion may be segmented differently. In other examples, this may include determining when a segment (or at least a portion of a segment) is to be formed, for example if this is at the beginning or end of an additive manufacturing process. In other examples, this may be based on thermal considerations.

Block 308 may, for example, comprise determining that at least one segment has a variable thickness, wherein the thickness of the segment in a first object region comprising a surface of the object having the first orientation is different than the thickness of the segment in a second object region comprising a surface of the object having the second orientation. This may result, for example, in generating an object face to provide different functional or appearance attributes.

Block 310 includes generating additive manufacturing control instructions from nested object segments, wherein the additive manufacturing control instructions for each segment are generated using different processing parameters. In some examples, this may utilize at least one mapping resource, such as a look-up table. For example, the processing parameters may include allowing selection of at least one fixer, where the available fixer and/or the amount to be applied varies between segments. The processing parameters of the inner segment may, for example, allow for the selection of a "carbon black" fixer (in some examples in combination with a low color fixer), while the surface segment may allow for the selection of a low color fixer and not a carbon black fixer. The outer peripheral segment may allow for the selection of colorants to provide a larger color gamut than the inner segment. The "atmosphere" segment or segments external to the object may vary due to the availability of particular refiner and/or colorant selections.

Block 312 includes generating an object using additive manufacturing based on the control instructions. For example, this may include forming a continuous layer of build material on a print bed and applying a print agent according to control instructions for the layer and exposing the layer to radiation, resulting in heating and fusing of the build material.

In examples where segmentation is performed on a slice-by-slice basis, each of blocks 302-310 may be performed on a slice-by-slice basis. In other examples, the object model as a whole may be segmented and then sliced, in which case block 306 may be performed for each slice, or the slicing operation may be performed after performing block 308 or block 310.

Another aspect of the geometry that may be considered is the orientation of the segment within the object (e.g., whether it is in the vicinity of a forward facing surface, a rearward facing, an upward facing surface, a downward facing surface, or a surface formed at some specified angle).

Fig. 4 is an example of an apparatus 400 comprising processing circuitry 402. In this example, the processing circuitry 402 includes an object segmentation module 404 and a model evaluation module 406. In use of the apparatus 400, the object segmentation module 404 represents a virtual build volume comprising at least a portion of an object to be generated in additive manufacturing as a plurality of nested segments comprising a peripheral segment and an object core, for example as described above, and the model evaluation module 406 determines a relative volume composition of the segments from data relating to the object based on a geometry of the object. More specifically, the object segmentation module 404 determines the shape of the peripheral segment based on the determination by the model evaluation module 406. The shape may follow the contour of the surface of the object or may be different therefrom. The shape may be determined such that at least one peripheral segment has a variable thickness. In some examples, object segmentation module 404 may generate a virtual construction volume from the received object model, and generating the virtual construction volume may include modifying the received object model, for example, by segmenting the received object model.

For example, as described above, the model evaluation module 406 may determine a plurality of local relative volumetric compositions of segments within the object based on the local geometry of the object and at least one expected object property. For example, in the area of a smaller object feature, the core segment may occupy a relatively larger relative volume than in the area of a larger object feature. In another example, the core segments may occupy a relatively larger relative volume in a lower region of the object than in an upper region of the object. In another example, peripheral segments (e.g., surface segments) may occupy a higher relative volume in an intended front side of the object than in an intended back or bottom side where a lower level of appearance quality may be allowed.

The processing circuit 402 may perform the method of fig. 1 and/or the method of at least a portion of fig. 3.

Fig. 5 shows an example of an apparatus 500 comprising processing circuitry 502, the processing circuitry 502 comprising an object segmentation module 404 and a model evaluation module 406, and a control instruction module 504. The apparatus 500 further comprises an object generation means 506.

In use of the apparatus 500, the control instruction module 504 generates control instructions for generating the object, wherein the generation of the control instructions uses different processing parameters for different segments, e.g. as described above with respect to fig. 3.

The object generation device 506 will generate the object according to the control instructions and may include additional components not described in detail herein for this purpose, such as a print bed, build material applicator, print agent applicator, heat source, and the like.

The apparatus 500 may perform the methods of fig. 1 and/or fig. 3.

Fig. 6 is an example of a tangible, non-transitory, machine-readable medium 600 associated with a processor 602. The machine-readable medium 600 may be non-transitory and stores instructions 604 that, when executed by the processor 602, cause the processor 602 to perform processes. Instructions 604 include instructions 606 to segment a data model comprising a virtual build volume of at least a portion of an object generated in three-dimensional object generation into at least one peripheral segment arranged around a core segment, wherein the at least one peripheral segment has a variable thickness. For example, the peripheral segments may be thicker in one region than in another region.

In some examples, instructions 604 may include instructions for causing processor 602 to segment the data model of the object to have a segmented thickness in the object region based on at least one of: (i) a local size of the object, (ii) a local direction of the object feature, (iii) a vertical position of the object region within the object in the manufacturing direction, and (iv) an expected object property (which may include an expected property gradient within the object).

In some examples, instructions 604 may include instructions that cause processor 602 to determine control instructions for generating the object by applying the first processing parameter to the first segment and applying the second processing parameter to the second segment. For example, the application processing parameters may include the use of particular mapping resources.

The machine-readable medium 600 associated with the processor 602 may perform at least one of the blocks of fig. 1 and/or 3, and/or may provide the modules of fig. 4 or 5.

Examples in this disclosure may be provided as any combination of methods, systems, or machine-readable instructions, e.g., software, hardware, firmware, etc. Such machine-readable instructions may be included on a computer-readable storage medium (including, but not limited to, disk storage, CD-ROM, optical storage, etc.) having computer-readable program code embodied therein or thereon.

The present disclosure is described with reference to flowchart illustrations and block diagrams of methods, apparatus, and systems according to examples of the disclosure. Although the above-described flow diagrams illustrate a particular order of execution, the order of execution may differ from that depicted. Blocks described with respect to one flowchart may be combined with blocks of another flowchart. It will be understood that each block of the flowchart illustrations and block diagrams, and combinations thereof, can be implemented by machine-readable instructions.

The machine-readable instructions may be executed by, for example, a processor of a general purpose computer, special purpose computer, embedded processor, or other programmable data processing apparatus to perform the functions described in the specification and drawings. In particular, a processor or processing device may execute machine-readable instructions. Thus, the functional blocks of the apparatus and device (e.g., object segmentation module 404, model evaluation module 406, and control instruction module 504) may be implemented by a processor executing machine-readable instructions stored in a memory or a processor executing instructions embodied in logic circuits. The term "processor" should be interpreted broadly to include a CPU, processing unit, ASIC, logic unit, or programmable gate array, etc. The methods and functional modules may be performed by a single processor or divided among multiple processors.

Such machine-readable instructions may also be stored in a computer-readable memory that can direct a computer or other programmable data processing apparatus to operate in a particular mode.

Such machine-readable instructions may also be loaded onto a computer or other programmable data processing apparatus to cause the computer or other programmable apparatus to perform a series of operations to produce a computer-implemented process such that the instructions which execute on the computer or other programmable apparatus implement the functions specified in the flowchart and/or block diagram block or blocks.

Furthermore, the teachings herein may be implemented in the form of a computer software product stored in a storage medium and comprising a plurality of instructions for causing a computer device to perform the methods recited in the examples of the present disclosure.

Although the methods, apparatus and related aspects have been described with reference to certain examples, various modifications, changes, omissions and substitutions can be made without departing from the spirit of the disclosure. Accordingly, it is intended that the method, apparatus and related aspects be limited only by the scope of the following claims and equivalents thereof. It should be noted that the above-mentioned examples illustrate rather than limit what is described herein, and that those skilled in the art will be able to design many alternative embodiments without departing from the scope of the appended claims. Features described with respect to one example may be combined with features of another example.

The word "comprising" does not exclude the presence of elements other than those listed in a claim, "a" or "an" does not exclude a plurality, and a single processor or other unit may fulfill the functions of several units recited in the claims.

Features of any dependent claim may be combined with features of any independent claim or other dependent claims.