generating vector displacement maps.

[super gnu]

they are intriguing, but ive never used them as it seems there is no way to actually generate them without using zbrush or similar.

is there a method to generate them from a mesh in max, or a nice small utility like xnormals?

[super gnu]

ok so nudging this.. it would be *very* useful given the woefully underused vector displacement function in vray, for somebody there to work out / produce a quick tutorial on how to use xnormal (free) to generate a vector displacement map from a high res model, in the correct format,

and the settings in the vray displacement modifier. for use on the specified lowres model to get back to an accurate copy of the highres model..

i know xnormal can do vector displacement maps (direction maps) from a high/low res mesh pair..

i know vray can render them..

but getting the correct result at the end is escaping me.

there is basically no info online.

[Ihno]

I stumbled upon this:
https://docs.chaosgroup.com/display/...ectorDisplBake
Haven't tried it though.

[super gnu]

ah.. hahah.. no way. not only is there a way to do it directly with vray, theres even some basic instructions.. why had i never heard of this?

ill have to give it a go. i assume the settings for displacement amount and shift should be replicated on the displacement modifier? how does that work with differing scene units?

[super gnu]

nope, cant seem to get it to work.. ive followed the instructions, ive got a very high res 3d person scan (16m polys) and a retopo version at 500k polys.

they are perfectly aligned with eachother, and the scale and pivots match. they both have good uv mapping.

ive applied the vraybakevector material on the low res one, and set the high res as the target mesh.

i adjusted the max displacement amount to 0.1m, as this easily covers the maximum surface deviation between the two models (max is probably about 1cm in reality)

i set the shift to -0.05m.

added a domelight to scene, as without that, the render to texture renders black.

in rendertotexture interface, with low res mesh selected, i open render to texture, and set "use existing mapping" add a vray complete map, set it to 5k res

hit render, and i get this:



given there is surface deviation all over the model, i can see there is no possibility this is a correct map.

any suggestions? i cant upload models.

[super gnu]

tried it with a sphere, and a low poly sphere.. this is the end result with the displacement modifier on lowpoly sphere set to vector/tangent, and amount/shift set to match bakevector material settings
.

[super gnu]

Anbody at Chaos care to give a reliable workflow for this handy looking material? obviously the one provided doesnt work or id get two spheres in the above test.