Tears in udk dx11 tesselation

SamboMambo · Apr 2012

trying to get stuck into a bit of dx 11 tessellation in udk, but i'm getting seams/tears anywhere there is a break in the uvs, this is when i use a height map with either mtm_flattesselation or mtm_pntriangles.

I know epic state in the their docs that you will get tears but is there anyway to fix or minimise them?

cheers.

Olli. · Apr 2012

All i know about tesselation comes from cryengine3, so what i say might not translate 100% to UDK but maybe some of it will help.

First of all, there should be a displacement offset value somewhere, which defines the +- of the mesh.. if you lower that the mesh should compress a bit, and possibly covering the seams.

theres no way to get no tear on UV seams in hardware tesselation.. all you can really do is place your seams wisely.

gsokol · Apr 2012

Yea, I have this in my WIP Environment as well...I haven't tried tackling it yet...try puting the borders of your heightmap to a medium gray where the seam would appear.

Xendance · Apr 2012

Check "enable crack free displacement" in the DX 11 material properties.

SamboMambo · Apr 2012

thought you were taking the piss, but there it is!

cheers!

SirCalalot · Apr 2012

Just be wary that "Crack Free Displacement" isn't 100% effective, but it should help to alleviate some of the problems.

SamboMambo · Apr 2012

yeah i'm still get some cracks at uv breaks, looks like we are going to have to add more polys and chamfers into our low poly meshes to make them work better with tessellation...

SirCalalot · Apr 2012

Having the mesh topology clean and uniform helps a helluva lot in tessellation too - but that probably goes without saying.

Tears in udk dx11 tesselation

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