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Troubleshoot texture extraction

The following lists common problems related to texture extraction and possible solutions:

Problem/Error message | Possible problem | Possible solution
--- | --- | ---
No map output | File names were not specified correctly in the options window. The application runs out of memory before completion. | Ensure that the map name is specified correctly in the texture extraction options window. Try a smaller resolution map, lower bit depth, or add more memory (RAM) to the computer.
Mudbox fails to extract a displacement map and outputs the following error message: Mudbox cannot use the Subdivision Locate Method on these meshes, because they do not have the same base-level topology. Set Method to Ray casting and try again. | The polygon topology differs between the models being used for the extraction. The Subdivision method requires that the topology be identical for texture extraction. | If you need to use the Subdivision method, and are extracting from the base level to a higher subdivision level, there is likely a possibility that a three-sided or non-quad polygon exists at the base level which must be removed or converted to a four-sided polygon before Mudbox can perform the extraction. The easiest way to do this is to simply subdivide the model once so any three-sided polygons get split into a four-sided polygon. This increases the density of the model. Otherwise, you'll have to edit the model in another application to remove the triangle or use the Ray cast extraction method.
Displacement map appears black or without expected detail. | No displacement height information has been recorded. Displacement values between target and source are either zero or negative values. The Search Distance value is set too small to capture any detail or the Search Distance is set too large and the Normalize to Search Distance setting is turned on which results in a smaller stored displacement values. | Ensure the Search Distance is set to encompass both the source and target meshes as accurately as possible. In general, setting the Search Distance too large can be just as bad as setting it too small. When the search distance is too large, unwanted surfaces may interfere with obtaining a clean extraction. For example, when extracting a map on a biped character the Search Distance might pick up the opposite leg and vice versa. For more information, see Extract a normal or displacement map.
Displacement map indicates sculpted details that plateau or their height appears clipped. | The source and target surfaces are not fully within the region defined by the Search Distance setting. | Ensure that the source and target models are positioned and aligned correctly. When extracting for subdivision surfaces, you may need to align the low resolution and the subdivision surface in a 3D modeling application and re-import the low resolution surface, and extract again. Ensure the Search Distance is set just large enough to encompass both the source and target meshes. For more information, see Extract a normal or displacement map.
Displacement map produces stair-stepping artifacts, banding, or detail appears missing when the target surface is rendered. | The bit depth you selected in the extraction options is set too low. The UV shell covers less area (pixels) in the texture map than what is required to preserve the sculpted detail. The scale of the UV shell in relation to the texture image has an impact on how many pixels get assigned to represent the detail on the high resolution model. When a large UV shell with a lot of sculpted detail occupies a very small area on the texture image (UV tile) it will appear soft by comparison to a similar sized UV shell occupying a larger area on the texture image. This is because the detail is represented by fewer pixels in the extracted texture image. | Increase the bit depth for the displacement map output to 32 bit (floating point) and extract another displacement map. Increase the area that the UV shell covers by scaling it larger in the original 3D modeling application, import the target model to Mudbox again, and extract another map. Then, extract a map at a higher resolution.
The details on the target surface appear soft or blurred when rendered. | If the Smooth Source Model option is on, a smoothed approximation of the high resolution (source) surface is used which can result in a blurred or soft appearance when the resulting target surface is rendered. | Turn off the Smooth Source Model option in the Texture Extraction options window.
Displacement map produces abnormal spikes or artifacts when rendered. | The source and target surfaces are not aligned closely or the Search Distance is set too large to accurately capture details. UV texture coordinates may be of poor quality. | Ensure that the source and target surfaces are positioned and aligned correctly. When extracting for subdivision surfaces, you may need to align the low resolution and subdivision surface in a 3D modeling application, re-import the low resolution surface and extract again. Ensure the search distance is set just large enough to encompass both the source and target meshes. Ensure the UVs are laid out on the low resolution version of the model following the requirements described in Prepare a model for painting. Many of the criteria for creating UVs for painting on a model are also valid for ensuring a successful texture extraction.
The extracted displacement/normal map appears to crease or fold over on itself in localized areas when the target surface is rendered. | When the high resolution source and lower resolution target surfaces are not closely aligned, Mudbox cannot accurately sample between the two surfaces, particularly in concave surface areas. | Ensure the source and target surfaces are closely aligned, particularly in the concave areas. This may require editing the low resolution mesh in the original 3D modeling application so it better matches the high resolution source, importing it into Mudbox again, then re-extracting the texture.
Seams appear on the rendered version of the model when the extracted texture is applied. | The polygonal faces and the UV faces are very different in shape by comparison There is too little space between the UV shells as they appear in the UV View. Many UV shells are rotated at disparate angles to each other. | Ensure the UVs are laid out on the low resolution version of the model following the requirements described in Prepare a model for painting. Many of the criteria for creating UVs for painting on a model are also valid for ensuring a successful texture extraction.
The extracted texture map appears soft when rendered in regions where a lot of detail occurs on the original high resolution mesh, even though I extracted a high resolution map. | The scale of the UV shell in relation to the texture image has an impact on how many pixels get assigned to represent the detail on the high resolution model. When a large polygonal face with finely sculpted detail occupies a very small area on the texture image (UV tile) the detail gets represented by fewer pixels in the extracted texture image. This can cause the map to appear soft in comparison to a similar sized polygonal face occupying a larger area on the texture image (UV tile). | Before exporting the model from your 3D modeling application and importing it to Mudbox, scale UV shells that have more importance to the rendered model larger so that they will have more pixels assigned to them on the extracted texture.
Sculpted regions appear smeared or compressed together when the target surface is rendered. | If the target surface and extracted texture map are rendered as a subdivision surface and neighboring UVs are unevenly distributed/proportioned in relation to each other, the edges can be repositioned as a result of the subdivision process at render time. This can cause a smearing or the appearance of compression in the sculpted detail. | Modify the UVs to compensate for the compression that can occur then import the model to Mudbox and extract the texture again.
Ambient occlusion - The following message appears when attempting to extract an ambient occlusion map when I click Extract. The model mesh has no UVs. Mudbox needs UVs to generate Ambient Occlusion Maps. Try selecting Recreate Level UVs under the Mesh menu | Unless you are extracting the ambient occlusion map in Ptex format, the target model must have UV co-ordinates. The model (or current subdivision level) doesn’t have UV texture coordinates. UVs must exist on the model and at the current subdivision level for an ambient occlusion map to be extracted. | If the model has no UVs, they must be created in another 3D modeling application and an updated version of the model imported to Mudbox. If the model has UV texture coordinates but not at the current subdivision level, you can create UVs for that level by selecting Mesh > Recreate Level UVs. For more information, see UVs overview
Ambient occlusion - The same ambient occlusion map appears on multiple objects in the scene when previewing the ambient occlusion maps. | The objects have the same material assigned to them. Extracted ambient occlusion maps are assigned to the diffuse channel for a material. If all objects use the same material, the same map or painted texture appears on all of the objects when they are previewed. The other extracted maps are correctly generated, but do not appear in the preview. | When extracting ambient occlusion maps for multiple objects in the scene, assign separate materials to each object before extracting the map.
The normal map doesn’t appear correctly on the model. | The Compatibility and Coordinate Space settings on the Mudbox Material may not match the settings used when the normal map was extracted. | Experiment with the Compatibility and Coordinate Space settings on the Mudbox shading material to see if these improve the normal map display.
Applied normal map displays incorrectly. | The subdivision level on the target model may be too high so that both the original sculpting and the normal map that was extracted are applied to the model resulting in twice the effect. | Set the subdivision level on the target model appropriately so the normal map preview accurately reflects how it will appear when rendered. Failing to do so will cause the model to appear with both the high resolution sculpting and the normal map effects which may not be desirable.