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View Full Version : are non-planar polygons a problem on a non subpatched mesh?



shenhua
12-17-2015, 05:46 PM
Hi

I usually do models in subpatch, so I know that non-planar polygons aren't a problem for layout because it triples them on render.

I seem to remember that I red somewhere that non-planar polygons can cause layout crashing?

So I've got this model... made to be subpatched. I have subpatched it - but that is a very high polygonal model, so I went to freeze it - and I ended up with some % of non-planar polygons.

I threw it into the layout... looked around, VPR, short test render - it works.

BUT I am worried maybe it's like at some angle etc it might crash the render?

So my question is: Are non planar polygons a problem for a model that is not subpatched? Or is it like layout has some magical way to get around them even when you won't subpatch the mesh?

I'd like to know because if it's a problem (and might make my software start crashing at some point) I'd probably try to deal with the non-planars. But if it's not a concern anymore, I'd just leave them alone.

Thx in advance.

ernpchan
12-17-2015, 05:52 PM
If you triple the model you should be ok as that'll get rid of the non-planars.

Greenlaw
12-17-2015, 05:58 PM
Non-planar polygons in a subpatched object shouldn't be a problem for Layout.

If you freeze the object though, then it's no longer a subpatched object, and any non-planar polygons may result in a render errors. A quick way to fix this is to select the non-planar polygons using Polygon Statistics in Modeler and triple them. In cases where the flow is critical, you may wish to split the non-planar polygons manually.

That said, LightWave can be very forgiving about non-planar polygons, more so than other 3D packages. In many cases, you should be fine.

G.

shenhua
12-17-2015, 06:09 PM
131484

I tried to triple the whole model, but that gave me this kind of irregularities of smoothing in some areas (especially round areas and some poles).

Tripling some of the model - that sounds like an idea.

So I guess I can conclude that the workflow of model in subpatch -> freeze, was wrong way to take, unless I was aiming to triple it anyway, because it will ultimately give those non-planar polygons?

I thought I can escape the high poly count slowdown by freezing the bastard (well I actually mean to make the high poly count workable because it works for me much better than if it has to calculate the subpatch every time) - but now I'm worried about those non-planar polys :(.

Greenlaw
12-17-2015, 06:50 PM
Yes, if you don't need to freeze the SubPatch object, don't do it. Most users will only freeze the object if there's is a specific technical issue to address. If you want to reduce the number of polygons in a SubPatch object, you can lower the Render SubPatch Level for the object in Layout.

In some situations, you will want to set the Display Level to match the Render Level before submitting the render--this can significantly speed up rendering for super dense SubPatch meshes, especially for deforming characters. But if the resolution isn't too high, I wouldn't worry about it too much.

G.

shenhua
12-17-2015, 06:52 PM
Thanks for the replies guys. I guess I will just settle for tripling parts of it. To cut my losses and plan it better for next model in the future.

Snosrap
12-25-2015, 08:17 PM
I've never known non-planar polys to crash layout. The only issues you could have is rendering errors.

3dbr
12-26-2015, 12:02 AM
Try "Normal Corrector"
https://www.lightwave3d.com/assets/plugins/entry/normal-corrector/

jeric_synergy
12-26-2015, 01:07 PM
I've never known non-planar polys to crash layout. The only issues you could have is rendering errors.
Seconded: ugly look, but no crashes.

You may be able to address your smoothing issues to some degree by adjusting the Smoothing Angle parameter in the Surface Editor. I can never remember which way it goes, but it can certainly effect the look radically.

You may also be able to 'recover' un-necessarily Tripled polys back to quads using.... TrigonX? Use on SELECTED polys to limit its effect.