displacements

[alexx]

hmm..

to get a result that is close to what you want, you need to crank up the threshold and the sample values in the objects AE.
but then it becomes terribly slow..
i have checked old softimage when it got the adaptive displacement tesselation.. hell. THAT one is quite a lot faster and better..
maybe mental ray can help?

cheers

alexx

[Duncan]

I would recommend you avoid using the feature based displacement mapping( unfortunately this is the default ) and go with fixed tessellation combined with a bump map. When creating the displacement first turn off feature displacement on your surface. Now when you create a displacement map, a bump map connection should automatically get added. Note that if feature based displacement is OFF and there is no bump map, the triangle normals will render as if for the original non-displaced surface. This is so the bump will not add a double-displacement and avoids certain artifacts.

Now set the tessellation of the surface high enough that the profile of the surface is good enough for your application. Display render tessellation can be useful in this step. I would also tend to use uniform rather than adaptive tessellation, especially if the surface is morphing( this would avoid pops due to tessellation changes).

The feature based displacement is good for things like displaced logos and tiles, but poor for complex displacements like terrain and fractals.

Duncan

[iC4]

will try this duncan thx! and this method creates "polys" and is not only a bump map?

The feature based displacement is good for things like displaced logos and tiles, but poor for complex displacements like terrain and fractals.

yeah noticed that.....but I need it for a terrain ;)

[alexx]

if you want to create terrains it might be a good idea having a feature displacement map, that is mostly black and white.
if you use a standard fractal like shader you will get so much detail, that is wont be fun.
i had good results by using first a high contrast map to displace the ground and then converting it to polies which i then bump mapped again with a similar fractal like the displacement one.

if you do that without converting to polygons it all tends to get very slow during render time..

[Duncan]

this method creates "polys" and is not only a bump map?
Yes. It displaces the surface(at render time), but relies on a bump map for the fine detail. You can convert both types of displacement to polys if you need the actual displaced surface to preview object placement and such. The render result will be more accurate if you render the displacement with the bump, rather converting to polys and assigning a shader with a bump. It will also use less memory, as polysets in maya consume a fair bit of memory. You might use convert to poly just for a low res mesh for positioning that you don't actually render.

Duncan

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