Low poly modeling triangulation issue

[reidsteven]

looking for someone with experience in very low poly modelling? I'm starting a project with the aim of recreating a the Chicago scene from perfect dark on the n64, the aim is to stick to the original poly count. However I'm coming across a problem where the model looks considerably worse after triangulation. The problem is that when a quad isn't completely flat when the triangulation is being calculated it splits that quad in to two flat surfaces that are no longer flat to each other which causes shading problems. I can apply smoothing  but it only masks the problem and it's still noticeable. I'm wondering if there is a way to avoid this or any methods I can use to improve the look of my models after triangulation.

I've linked a picture so you can get an idea of how few polygons I'm working with. Usually I would just use smoothing to deal with the problem but when you're working with so few poly's the problem is much more noticable

Any help would be greatly appreciated. 

[Anonymous]

Perhaps would be easier to understand the problem if you provide images of how looks the model with problems showing the smoothing problems and the 3d models.

[miledrizk · Accepted solution]

Hi,

To avoid this, you need to keep your polygons flat, there is not other way,

Under the hood, it's all triangles, so a flat polygon is just two coplanar triangles,

Nothing can be done to change this behavior. So you need to find a modeling strategy

That avoids any twisting in your polygons.

[reidsteven]

Thanks I was afraid that would be the answer, bit of a pain trying to keep flat poly's when you're working with so few. Appreciate the help.

[reidsteven]

Thanks for the reply appreciate it mildresk has answered the question so I'll not bother but I'll make sure and do so next time I have a question. 

[Anonymous]

Not sure if I understand the problem, but are we talking here that we should keep a quad polygon planar? 

[reidsteven]

Yes when a non flat quad is triangulated it makes two faces that no longer have the same angled faces. Here's a demonstration  notice the quad appears flat and shades as such. but once triangulated you get two differing angles tri's

[Anonymous]

That is controlled by the normals of the object and should be able to be corrected with smooth groups or other systems. In the case you show the normals of each face are not aligned when they should, for example assigning the same smoothing group.

Normally very low poly objects will have lots of non planar quads that anyway will be converted to triangles in order to be displayed in the engine. Errors can appear if the normals of the object are not correct or the process of conversion from quads to triangles is not done correctly.

When exporting from Max you need to ensure smoothing groups and preserve edge orientation are ON as it what controls both. Obviously the import settings of the engine must be also able to read both.

It is possible also triangulate in MAX before exporting to be sure the conversion is done correctly with the edit mesh modifier in edge mode, select all edges and set visible. This avoids the problem that the target application is not able to read the edge orientation and flips edges.