View Full Version : Strange Render Thingies

05-20-2010, 12:22 AM
These 2 Renders are the exact same object, 1 rendered in lightwave, 1 rendered in modo. The modo render shows no artifacts while the lightwave render has tons.

I really love lightwave more, please tell me what i'm doing wrong =[


http://img38.imageshack.us/img38/2809/render1h.png (http://img38.imageshack.us/i/render1h.png/)


http://img25.imageshack.us/img25/1505/render2d.png (http://img25.imageshack.us/i/render2d.png/)

Thankyou as always for how helpful you guys are, any help would be great :D

Edit: Oh and yes I have tried running normal corrector script to no avail :(

Edit: Wow Even My normal solution of tripling the ngons doesn't fix the problem in this situation either :( I am stumped.


05-20-2010, 12:32 AM
Smoothing setting wrong?

05-20-2010, 12:43 AM
have tried the smoothing angle of 40 (which is what it's set to in modo) and various other numbers to no avail (89.5, etc.)

05-20-2010, 01:40 AM
can you post a fragment of the object, the part that is bad? :)

05-20-2010, 01:50 AM
heres the object.

feel free to have your way with it ;) Thanks again


P.S it has an occlusion node, so be sure to turn the light down to 0% before rendering so you can see stuff better.

05-20-2010, 06:29 AM
Hmm, I dont have LW infront of me, but isn't there a distanse type setting in the occlusion node? could it be that one.. Looks like a occlusion detail miss of somekind.
But thats just by thought. Im sure that someone with acsess to LW can awnser better.

05-20-2010, 06:39 AM
Id check out for non planer polys or artifacts, what camera is it, classic or perspective, sometimes perspective does not like some objects.

05-20-2010, 06:40 AM
Ok wow that bit of the geometry is really very non-planar. You also have quite a few places where the geometry will suffer smoothing anomalies. which would take a while to fix, or you can always increase your smoothing threshold :D

05-20-2010, 07:05 AM
Yeah definitely allot of non planer polys there mate

05-20-2010, 09:03 AM
I managed to re-topologise that, but it's not ideal as the panel you've done is twisted by design. I'd recommend you re-model those bits as you're never going to get good smoothing on those. There's quite a few other areas on those 'twisted' faces where you've panelled things and they've got terribly non-planar polygons.

05-20-2010, 09:14 AM
Tobian could you explain if its not to long how you go about re topologising. Never really dont it before

05-20-2010, 09:31 AM
Sorry, when I said 'retopologising' I meant I rebuilt that section of the mesh using the shapes as cutting implements.. I wasn't using fancy techniques they use in Zbrush/3Dcoat etc, to alter the topology of the mesh.

05-20-2010, 09:52 AM
Ok mate, thought you had a method i didnt know about :):):)

05-20-2010, 12:14 PM
Wow this one made me head twist. I run Normall Corrector and some poly went crazy and flipped. First time that i tripled it, the render looked bad, but the second time it looked good.

Short story is:
You have a lot of concave, non-planar, n-gons going on (you just hit the 3 main issues when it comes to polygons normals :D)

I was more lazy then Tobian. I just used what you had and make some "connect"'s here and there, to brake those concave n-gons to convex quads. Also some edges i created end in a n-gon, but since it's in a planar polygon, it's ok.

Another thing. (image 2) those bevels you have, you sould merge the 2 vertices into a single vertex. This is what cause the Normal Corrector going crazy on them.

In the end i just ran the plugins Janitor and Normal Correct, to clean up.

Funny fact that Modo handled these better. But you can be more carefull in the modeling.


05-20-2010, 12:18 PM
tobian you really are a guru and a life saver. I will do my best to remake the messed up parts.

Why does it render just fine though in modo with non-planars and ngons and lightwave render has such problems with it (there are still problems in your render on the edges). There isn't some render setting I can switch on to remove these artifacts, my smoothing threshold in modo was 40 degrees.

Edit. Probiner, I quiet your method, I will go about doing it on my own, can I ask you how can I tell a convex polygon from a concave polygon? Also where can I get my hands on the janitor plugin and what does it do? :) Big Thanks to you for always being awesome


05-20-2010, 12:30 PM
from the unreal engine documentation about convex concave polygons :D


Janitor does some shores that you have to do when you are finished modeling and you want to make sure it's all clean. I normally uncheck '0 polygon points' and 'triple nonplanar'.

for plugins just go in one of these and make a search:

05-20-2010, 04:02 PM
I would never blindly triple a nonplanar as you do need to control where the cuts are.. the problem with most of that model is it was REALLY nonplanar. The way you'd modeled it meant you had a twist in the main face, which you then cut into.. but the problems start racking up if you boolean/stencil/knife into nonplanar polygons, as the cutting system has to kinda guess where to put the cutting point. And If you did these in Modo it did a worse job than LW did of it when I re-did it LOL... There's a bunch of other problem areas, I just didn't want to spend all day doing it, it'd be faster to re-design the flow of the topology and save your bevels as stencils to cut in once you've done that.

As for the render issues.. actually I think the main issue was the use of the ambient occlusion shader, as it didn't cause as much of a problem without it on.. obviously Modo's ambient occlusion is as tolerant as it's rendering engine is. LW's 'perspective' camera is also a LOT less tolerant than the old classic camera is, but the speed gains and better rendering options mean it's a no-go for me, but you might prefer it? :) Since Modo's rendering engine will be more akin to 'classic' than 'perspective' that's probably why it's more tolerant... But those are some funky polygons you have there! :D

To me it almost looks like you have moved points in the XZ plane once the cuts were put in, which is a no-no unless you have absolutely no height in Y. it also looks like you did a lot of your insets by eye, which is something I'd never do, but then everyone has their own style of modeling :D