displacement map instead of normal map?

[super gnu]

im currently fiddling with the whole "bake details from highres mesh into lowres one with normal map" thing.. tried xnormals etc.. i also fiddled with the projection modifier in max.
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it got me thinking.. it would be nicer to use displacement.

is there a way to generate a displacement map from a highres mesh to use on a lower res version?

i guess it would need to be a vector displacement map to work correctly...

[notamondayfan]

But why would you? Surely time needed to render a displacement of sufficient quality would be longer than just rendering the geometry?

[super gnu]

yes but a low resolution mesh is easier to edit and work with. for example at the moment im using a fracture plugin the smash stuff up. doing that on the full15 million poly mesh is basically impossible. at the moment im using normal maps to keep the detail as best i can.

[Ihno]

Also, it could be resolution dependent so a distant object/character wouldn't have to be so heavy.

Actually in VFX that's what they're doing.
A displacement map from a high poly version can be generated in xnormal or zbrush for example.

I tried that lately for a guitar string. I wanted it to have fewer polys in the distance.
It didn't work unfortunately. It displaced the geometry but it refused to subdivide it. And I don't know exactly why.
I think the low poly needs a minimum complexity I probably didn't reach..