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brianemsu2
10-17-2003, 05:30 AM
hi everyone,

I am looking for a way to get faster speed when I have a displacement map on an object.

For instance, say I wanted to make a model of the earth where its edges in the scene would have mountains that stuck out from the bounds of the sphere, giving more realism.
-Is there a way to use a bump map for the areas of the sphere that are inside the bounds and use a displacement map for the areas the are outside the bounds (or on the facing ratio normals of 0.. (that's pointing away, I think))

I am thinking this is going to have something to do with applying a samplerInfo node to a blender node with both bump and displacement files somehow. Here's where I am unclear- would the computer evaluate both bump and displacement before doing a lookup on the samplerInfo, which wouldn't save me any time...or- could this method be used to only evaluate the displacement at the edges somehow and evaluate only the bump in the center areas so I wouldn't have to wait on the computer to evaluate the displacement in areas where a bump would do.\
Thanks for any replies
-hope that all made sense
-Brian
Sciatica
10-17-2003, 05:49 AM
I really dont have an answer to your question.. but I thought of a flaw that may result using the samplerinfo node... being..
If you get it to work, you will probably notice some rapid jumping of the displacment maps... when your earth is turning.. I think there would be a noticble change over point where it switches from bumps to displacments.. It may end up being to sensitive on camera placement and such to really make it worth your while..

I really only have basic knowledge of the hypershade though.. so sorry if the above paragraph is.. out there... it was just something I though of.. :)

If I where you... I would probably just use displacment maps over the entire thing and suffer the extra render time.. but thats just me :)

Good luck! :thumbsup:
DeathBrain
10-17-2003, 06:05 AM
Originally posted by brianemsu2
I am looking for a way to get faster speed when I have a displacement map on an object.
Open your objects attributes, goto displacement maps, set extra sample rate to 0 then click calculate bounding box scale
You could also play arround with initial sample rate to help Maya calculate the displacement more faster, the default is 6
If the displacement looks to sharp, you could try to adjust (activate) advanced tesselation or curvature tolerance :)
Atwooki
10-17-2003, 02:33 PM
Not sure, but perhaps a ramp shader, with two values very close together:
Value one for the cam-side bumped surface, and
Value two for the 'edge' of cam surface, with a blend color node connected to a sampler info node, in the bump's 'Alpha Gain'.

edit: Perhaps also an expression utilising the 'feature disp.' and blend color/sampler info? (so that white of blend col is 'camera close' and uses feature displacement; and the other blend col is mapped with bump.... does that make sense?)

Atwooki
Sciatica
10-17-2003, 10:51 PM
I actually totally forgot about the bounding box feature :)

I just used it on one of my disp. map heavy objects and it took the render time down from about a 1:30 to 20 seconds! Saved my life! :)
brianemsu2
10-19-2003, 03:30 AM
thanks for the info..

I didn't even know that these calculate bounding box features existed. This should help me out.
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