Good Modeling Technique

Bob James · 28 Nov 2010, 01:15

I've been reading several posts involving plugins dealing with materials on back faces and want to be clear on good modeling technique.

Is this true?: Good modeling technique requires that the back faces have no materials added (that is, the back faces are all nil)

Rich O Brien · 28 Nov 2010, 01:38

It would be dependent on the render engine. I know Twilight can ignore backfaces as such and happily render away regardless. But vray used to have issues, although I think this was addressed on the last release.

Not sure about Thea as I keep my models nice and clean. As I imagine you do as well Bob!

Bob James · 28 Nov 2010, 02:09

@unknownuser said:

Not sure about Thea as I keep my models nice and clean. As I imagine you do as well Bob!

I'm currently using Thea and am trying to get started in Vue9.
When you say you keep your models nice and clean, what does that mean? (and since I don't know what that means I probably am not )

That's what I'm trying to pin down: what is "best" and "clean" - back faces nil or not [and whatever else is included in "clean"].

thomthom · 28 Nov 2010, 16:06

SketchUp is somewhat an odd out out when it comes to backfaces. Most other 3d modelling apps doesn't even display backfaces - if you look from the backside it'd be transparent. Unless you explicitly told it to display backfaces.

Id' not say it's good modelling technique to keep backface with no material, but it is good practice to keep control over frontface and backface orientation and keep them consistent - making sure the frontfaces are the ones visible.

When you have consistent and regular normals you have a more predictable mesh which makes modelling tools act more reliably. There aren't that many functions in native SU where this matters, but there is some. And plugins and extensions - in particular render engines cares much more about this.

Some doesn't use SU's backface materials, some do. VfSU for instance do that by default. But you will find odd things happen when you try to displace a mesh if you have faces flipped this way and that - as the displacement height is dictated by the face normal.