3D Displacement bug?

[RE:FORM_STUDIOS]

I have noticed a problem with the 3d vray displacement mod that causes my displacement to appear checkered.

After much fiddling with parameters, I have discovered that the displacement can be fixed by 'turning' the polygons to point the same way.



The square in the image relates to the four polys that I've 'turn'ed to face the opposite way.

Is this a bug or an expected property of the 3d displacement modifier?

Does anyone have any scripts to automatically make all polys have their triangulation aligned?

[DaForce]

Weird.. i have just had a quick play around and it seems to happy similar to what you say... i didnt quite get the extensive checkering that you got but definitly turning the polygons made a big difference as well as the size of the polygons.

Rather odd.

Couldnt find a proper fix for it either.
Although i didnt notice that if the noise wasnt so small... like 1.0 instead of your 0.1 it didnt seem to be a problem.

[RE:FORM_STUDIOS]

The good people at Chaos replied to my query nice and quick. The problem can be resolved by using a 2d displacement map.

We have received your mail about the problem with the displacement.
We have changed the type of it, using the 2D displacement, as
the 3D one needs the entire geometry to be retriangulated.
Also, lowered the noise size to 0.01, and the UVW MapMod now has some
tiling on U and V.

Please find the attached file.
Let us know if this works good for you !
If you still insist using the 3D type, you would have to retriangulate
the model on hand.

This is not a bug actually. You can get a similar look with the 3D
displacement, but raising the noise size to something about 400.0

I think the problem I had was that when trying to use 2d displacement ((which I eventually gave up on), I was using real-world-map size, which, I think, has some problems when used with displacement.

Oh and thanks to Nikki and Dmitri for all your help!

[DaForce]

so let me get this straight... if you want to use 3d displacement on any mesh you need to re-triangulate the mesh
seems odd!!!

[RE:FORM_STUDIOS]

No, I think it is because I was using such a highly tiled displacement map. Either that (or in addition to that) I was using a real-world-coord-uvw-map rather than standard uvw-mapping (can someone confirm the limitation?)

[RErender]

and it was a mess, I mean mesh from some other program, right?

[DaForce]

well i just made a plane, and and it did the same thing as yours... but not quite as bad... but turning the faces certainly made a difference. so it still strikes me as a problem
I also tried with and without a UVW map.. and default settings and made no difference.

[RE:FORM_STUDIOS]

Hmm... spline converted to poly... so yes, pretty messy to begin with.... but I did work it over and sort the topology out (all quads). The thing is, even after retriangulating, there were still strange variations in colour like in the example above.

So retriangulating improved the situation but didn't fix the problem.

In regards to creating the landscape-mesh, can anyone suggest a better workflow for creating a landscape mesh from an outline spline that gives a nice topology? For this model I imported the outline, added an editable-poly-modifier, added segments where required, removed uneccessary vertices, and then converted to an editable polygon.

[studioDIM]

After capping the spline, try using a MeshSmooth modifier, set to smoothness 0.99, and let it operate on triangles.

It should give you a nice, grid-type mesh...

See if this works for your spline (i tried it on a bendy one...)

Lele