Displacement: am I doing it wrong?

[arktoga]

Hello! I'm having troubles with SketchUp + Indigo and the Displacement option..
Displacement seems to generate artifacts if i use a low subdivision value.
They only disappear if use a crazy high one (around or more than 10), which makes it impossible to render anything besides small surfaces.
I tried with several textures, files and settings, but nothing seems to work.
What am i doing wrong?
This is kinda getting me crazy, cause without displacement renders look quite flat (obviously!).

I'm uploading some tests i did to clarify the situation,
each image is a thumbnail, but also has a link to the original size:


http://i.imgur.com/MSPGrvK.jpg


http://i.imgur.com/eFw2gxn.jpg


http://i.imgur.com/tf4aTzQ.jpg


http://i.imgur.com/cc2aoYk.jpg


http://i.imgur.com/vzzNKLL.jpg


http://i.imgur.com/LfcvNMy.jpg


http://i.imgur.com/EQ2pg93.jpg

[Zom-B]

first some insight into the values:

Gamma needs to be 1.0 for textures that don't use color information.

for Your A B and C values you can let A = 0. B is the displacement in meters. so 0.01 is 1cm.
with C you can centeer out the displacement so that a neutral gray will be no displacement, brighter get positive displaced, darker negative. C needs to be (0.5*B)*-1. A B of 0.5 would need a C of 0.25 to center the neutral gray.

Curvature Threshold ONLY gets used if you also set a Error Threshold! a Error Threshold of 0.001 works already nicely.
Also use the Pixel Threshold, so polygons don't get subdivided further that this Pixel size, BUT this value is aiming at internal Render resolution. if you have SuperSampling enabled @ 3 for example, then you need to set Pixel Threshold to 3 to have a effective Pixel Threshold of 1 in your scene!

Pixel- and curvature threshold are only used if View Dependency is enabled for subdiv!

To actually see the displacement export to indigo, set you material as diffuse and enable the "random triangle color" checkbox at the bottom of diffuse material settings.

This is great to debug your subdiv settings

[CTZn]

It looks like the cube geometry is merging with the plane geometry, forcing the later to bear new, unconvenient triangles. If that's true, you'd want to avoid the merging from SU.

[galinette]

Wouldn't bump be enough for this kind of material? You should try it.

If you really want displacement, try combining with bump. Displacement of very grainy and detailed maps like this one needs a very detailed mesh, as you noticed. Try using a blurred version of the map for displacement, and add some bump with the original map (or even better : substract the blurred displacement map from the original detailed map in PS, and use it as bump map - in other words, you displace low frequency features and bump high frequency ones, which uses each technique where it works best).

Etienne

[CTZn]

(or even better : substract the blurred displacement map from the original detailed map in PS, and use it as bump map - in other words, you displace low frequency features and bump high frequency ones, which uses each technique where it works best).

Excellent trick for the matter, thanks.