OTOY Forums

Hi ,
I have a wee normals issue that is ruining the appearance of some of my renders.
In the pics attach you see tris showing even after smoothing - unsmooth case shown for comparison.
This is particularly obvious in the middle band where the curvature is mostly in one direction.
The tris are not that good in a cg modelling sense - they are long and narrow but it is exported from a CAD program like that and I dont have control over it.
I would have thought though it would appear smoother than it does.
Is this primarily a fault of the mesh? I use Blender to prepare the scenes. Would it help to subdivide or such these faces?
Perhaps Octane should smooth this better or there could be a setting exposed to tweak the angle for normals smoothing?
thanks for ideas

try disabling the 'use vertex normals if supplied' in the OBJ import prefs panel prior to import, to let octane recalculate them, and see if that helps?

Radiance

Sorry to be slow getting back to this.
I tried your suggestion and its quite a bit better for some reason. Still a bit off here and there from what I would like but I'll use that until I figure out how to make the topo better. Thanks.
I tried selecting the ugly shaped faces and edge subdividing to make them less long and narrow but that didnt give the desired results - probably made it worse actually. Smooth vertices wasnt helpful either.
Perhaps it has deviations/waves away from a nice surface because of the CAD exporter accuracy. I'll try out some other settings etc in that and see if I can get an improvement.
I am not quite sure why the tris would show up like this though..I would have thought they would blend together but..
I asked Blender to select faces greater than 0.5 deg from a selected one and it doesnt find many either side so its fairly flat.
I'll keep experimenting

usually there are options in apps that export OBJ where you can define the quality of the vertex normals generated.
blender has this (high quality normals for rendering, which i recommend enabling)

Radiance