Troubleshoot general Fur issues

PolySmooth node causes Fur to flicker.

If files have polygon objects with Poly Smooth applied after skinning and the Smooth UVs option turned on, there will be flickering in the animation of rendered Fur, or the motion blur.

Solution: Turn off Smooth UVs in the smooth node.

When I comb my Fur, nothing happens.

Combing the Fur (painting Direction) basically changes the Polar value of the hairs, effectively rotating them on their axis. If you have no Inclination, and no Curl, all that combing will do is to spin the hairs around on their axis, so you will see no effect.

Solution: Set the Inclination to a value greater than 0 - e.g. 0.5. You will immediately see the results of your previous and future combing.

I painted Direction and now I want to reset it to the default, but I can't find a Direction map to delete.

Painting Direction writes out a Polar map based on the interpreted values of the brush direction, since it would be extremely difficult to represent a Direction map.

Solution: To reset the direction of the hairs, delete the Polar map by selecting it from the Details section and selecting Remove Item. You can also apply global changes to the Direction by flooding the Polar map in Artisan - for example, selecting Smooth and Flood to even out your combing.

When painting direction on polygons, sometimes the Fur does not follow the direction of my brush.

If your UV map is not one contiguous piece, your brush may be crossing a UV seam. When this happens, the UV pieces may be orientated differently in texture space, and it is impossible to determine the correct direction for all of the fur under the brush.

Solution: Display your UV borders when painting (Display > Polygons > Custom Polygon Display > Texture Borders). When painting close to the seams, make your brush small enough so that it doesn't paint on both sides of a seam at the same time.

I mapped an attribute in the fur description and baked it, then I broke the connection, but the fur still renders as though the map is connected.

Once an attribute map has been baked, you have to rebake to remove it after breaking the connection.

Solution: Break the connection, then select the required attribute in the 'Bake Attribute' pop-up and hit Bake.

Fur seems to be flipping or crawling on my deforming polygon surface.

Fur is placed on the surface according to UVs. If your UVs are changing over time, the Fur will appear to crawl over the surface. This can happen if you have your UV projection after a deformer, for example.

Solution: If possible, delete the history on your UV operations, or make sure they are upstream of the deformers. One way to remove the history on the UVs without losing the animation is to duplicate the mesh, delete the UV projection nodes on the original, and then use Mesh > Transfer Attributesto transfer the UVs back from the duplicate.

My disk is filling up with zillions of fur files - what can I do?

Once your render is complete, you can delete anything in your furFiles directory, furShadowMap directory, and furEqualMap directory - these are recreated each time you render, unless you are using an Advanced Fur Rendering technique. Do not delete the contents of furAttrMap which are prefixed by any scene name you still require - these are your Artisan and baked maps, and are needed to define the Fur. If you are happy with your final composite, you can also delete the contents of your furImages directory - otherwise you may want to keep these to use separately in a compositing application.

Solution: To have these files deleted automatically when no longer needed, turn off Keep Temp Files (off by default) and/or Keep Fur Images (on by default) in Fur Render Settings. The deletion takes place after each frame is completed.

Fur seems to be flipping, crawling or is incorrectly placed on my animated trimmed surface.

Fur does not understand trimmed surfaces per se, so they must be tessellated into polygons before being passed to the Fur Renderer. Unfortunately, if the trimmed surface is animated, the tessellation of that surface can change from frame to frame, causing the fur to flip or crawl. mental ray also does not deal well with Fur on animated trims.

Solution: Convert the trimmed surface to polygons, or model without trims

My rendered fur does not follow the contours of a surface that has a displacement map applied.

Displacement is only calculated at render time, so fur is not aware of it.

Solution: Apply the same map used for displacement to the Offset attribute the fur description.

I can't seem to paint values such as length to be greater than 1.

Because the Paint Fur Attributes tool uses grayscale maps to represent values, those values are always initially mapped to the 0 to 1 range.

Solution: Begin by flooding the surface with a value of 1. Then change the Map Multiplier and/or Offset values under the Details section for the appropriate attribute. For example, to paint Length values in the range of 0 to 5, set the Map Multiplier in the Length section to 5. You can now paint length values in this range - for example, mid gray with a value of 0.5 will produce a length of 2.5.