Hi All

Does andybody know a solution to the odd triangle artefact problem (cf. attached really bad example) except hours of stupid, boring postwork?

I know from several discussions at the POV-Ray news group that this is NOT a bug in Vue, it's inherent to raytracing phongshaded or "soft" triangles casting shadows on themselfs. However there are workarounds and I wonder if there is one for Vue.

Any help highly appreciated!

Best regards,
Christoph

A couple things to try, if those are terrains (not sure from the screen shot) you can increase their resolution and this should help. Another thing you can try, though this will add render time, is to add soft shadows to your sunlight (or whatever your source light is) and that may help things a bit.

There is one actually... the effect is vastly reduced if you smooth your polygons. Just double click on your 3D mesh and select a wider angle of 'smoothing' (like 80 or 90).

• agiel - www.linfa.net

Soft shadows and increasing smoothing angles does not help, I already tried this. The meshes in the image above all are smoothed with an angle of 60 (default). Additionally I did not see any difference between smoothing angles of 60 and 90. What does help a little bit is increasing mesh resolution (as with terrains). However just one step of subdivision only will blow up mesh size by a factor of 4 - and will not remove those artefacts to a level they are no longer visisble. More subdivision will cause Vue to crash (the well known and still unresolved memory bug with imported meshes ...) The only thing I found up to now that does the job is changeing the direction of light. If light is coming from the front, there are no artefacts, but no shadows and no contrast too. The result is a boring image, not exactly what I try to achieve.

Looks more like holes in the meshes. How do the meshes look in another app? Looks more like messed up geometry than artifacts.

No, the meshes are o.K. Rendered in Poser 4 there are no visible holes but more important, if I change the direction of the sunlight from right to left in Vue, I get other artifacts, whereas the bad spots in the image above look o.K. Alternatively I could turn up ambient light and then you can also see that the dark spots are not holes in the mesh but rendering artifacts. If anybody is interested I can upload images to proof this.

I just got into the habit of smoothing out these artefacts in photoshop or painter when they happen. If found it is a lot faster thn trying out to figure out how to prevent them :)

• agiel - www.linfa.net

Then I'm sorry I can't help, since smoothing the phong angle didn't work either. Maybe, just maybe if you smooth out the angle in another app, and export it to Vue you can get better results? Because it seems now it really is an angle issue. But at the end, Agiel is right I think. Easier & faster done in PS.

Yes, you convinced me! Although I hate fiddling around with brushes and smudge tools in PS it seems to be the easiest way to get rid of these artifacts! Thank you very much for your suggestions anyway!

Ok...I'm not sure but, that mesh you are using looks like a Hankster rock formation..right?
If so, the mesh has "issues". I noticed when I imported some of them into Zbrush that they have tiny protrutions jutting out of the mesh in some places. Which can be repaired in zbrush. But as Agiel said.....there is an easier way..photoshop.

It's a shame stupidity isn't painful.

You are right, it's a Hankster rock formation. I had similar artifacts with other meshes too, but this one is the worst by far up to now. I like the models a lot just the same ...

Check the normals direction in the object prior to import in Vue. If it's not the terrain resolution, 99% of the cases for such "wrong" triangles is inverted normals. Also it's a good idea to untriangulate your meshes in the modeling application. You are likely to end up with less polygons and a better mesh.

I would differ, about "un"triangulating. These look to me like non-planar polygons causing render errors, the best treatment for that being tripling them. Since by it's nature a triangle can't "fold" without adding vertices and becoming a polygon, a trinagle is far less likely to create these types of render errors.

I don't have a modelling application, so I can't try untriangulating and polygons. Vue can invert surface normals of meshes however. I tried this and then all parts of the mesh became invisible (not black), there was nothing left. I think this is an indication, that all surface normals point in the right direction, i.e. to the outside of the mesh. I'm not absolutely sure about this however.

you can try , 3d blender to untriangulating your mesh its free. your assumptions on the normals seems right to me.

for some free stuff i made
and for almost daily fotos