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View Full Version : Strange Artifact when modelling Logo



maschinsky
12-01-2014, 02:34 AM
Something that has bothered me now an again over the years using lightwave occured today in LW 2015, so I thought I ask around what I'm doing wrong here. 125771

The Logo has been imported as an EPS file and extruded. My idea was to slightly bevel the edges so they catch a little light and the logo looks classier. In order to get the hole in the A and the O, I copied the hole-polys into the background layer and sliced the holes into the letters. Then I extruded the logo and with the A I had the strange triangle happen that you can see in the attached picture. Strangely enough the triangle does not occur on the backside of the logo.

The next thing I did was delete the "front" polys and just leave the back ones and mirror the whole logo. That's why it now has that seam in the middle, but to no aveil the strange triangle comes in again.

Can anyone tell me what I'm doing wrong here? I have no double-points there either.

Sensei
12-01-2014, 02:37 AM
Can anyone tell me what I'm doing wrong here?

Left red double sided arrow is showing error in OpenGL triangulation routine.
Split n-gon to quads, and you won't have this in viewport.

I don't know what is showing right arrow. Don't see anything wrong there.

Skonk
12-01-2014, 05:15 AM
OpenGL doesn't like concave polygons (polygons that go in on themselves) and since lightwave allows us to have polygons with more than 3 points, its quite possible to make concave polygons.

Text is especially bad for it, L, H and so on all generate concave polygons.

Thing is, is just an OpenGL display issue; when you render in Layout, lightwave triangulates all the geometry anyway so issues like that don't show up in renders.

If it really bugs you, its easy to fix by either hitting shift + t (to tripple the polygons, but having nothing but triangles is generally not desirable) OR by splitting the offending polygons by selecting a couple of points between which you want to create a new edge and hitting L to split the polygon between those 2 points.

maschinsky
12-01-2014, 08:01 AM
Thanks for the clarification!