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Info

To match Displacement from previous versions of RenderMan, the following conversion may be of use:

To get a similar tessellation level, using a shading rate (deprecated) value of X would translate in using a micropolygonlength value of sqrt(X):

shading rate = 0.25, micropolygonlength = 0.5
shading rate = 1, micropolygonlength = 1
shading rate = 4, micropolygonlength = 2

...

In RenderMan for Maya, this attribute is enabled by the "Prevent polygon cracking" (rman_preventPolyCracks) check box. 

Hover over the image to see its effects.


Rollover Image Link
hoversmoothdisplacement_1_dsp.jpg
imagesmoothdisplacement_0_dsp.jpg
Before After Image Slider
methodoverlay
width100%
leftImageimage_galleries_uuid_smoothdisplacement_0_dsp_jpg-b4240a23-c538-4a46-ba56-21b2eaed643e
rightImageimage_galleries_uuid_smoothdisplacement_1_dsp_jpg-3ca84d73-fcef-4865-9815-53ecba4276f0

Note

"Prevent polygon cracking" should only be enabled when necessary as it uses a bit more memory. The amount used is proportional to the number of vertices in the mesh.

Notice When you hover over the image, notice how using smoothed normals warped the cube's displacement pattern and changed its appearance:

beforerollover-after-slider-macro-v2image-link
hover
methodoverlay
width100%
leftImageimage_galleries_uuid_smoothdisplacement_topo_0_jpg-6b518b9f-2224-4217-83f7-9a7b8d9e1dd2rightImage1.jpg
imageimage_galleries_uuid_smoothdisplacement_topo_1_jpg-15a93198-512d-49a9-ad78-2d11cc3117410.jpg

You can avoid that effect by inserting additional edges near sharp edges. This will limit the normal interpolation to the areas next to the edge and generally preserve the original appearance.

beforerollover-after-slider-macro-v2image-link
hover
methodoverlay
width100%
leftImageimage_galleries_uuid_smoothdisplacement_topo_0_jpg-6b518b9f-2224-4217-83f7-9a7b8d9e1dd2rightImage2.jpg
imageimage_galleries_uuid_smoothdisplacement_topo_2_jpg-b521bc27-e766-4be6-a57e-389cb94287530.jpg