View Full Version : noob subD question and mirror

10-26-2008, 06:47 AM

I'm working on a model tutorial from simplylightwave of the defiant space ship.

The narrator is using 8.5 in the tutorial and using the sub-patches for smoothing.

I'm using v9.5 and I've got subd set to catmull clark.

When I mirror the model and turn on subD there are holes in the mirrored part of the model. If I use the older sub-patch the model is fine.

After messing with it a bit, it seems related to setting edge weights. If I set the weights back to zero 99% of the model will smooth using catmull-clark fine.

There are a few polys that I have had to delete and rebuild - and they aren't on the edges that are mirrored and are fine on the "original" side of the model.

Since I'm very new to Lightwave I'd like to ask if there are "rules" to subD modeling using catmull and lightwave or if I may be doing something wrong.



10-26-2008, 10:22 AM
I believe this is one of the long standing bugs with Newteks implementation of CC subdivision. I don't use them because they still underperform but from what I remember, mirroring doesn't work if you already have edge weights applied. You'll want to mirror first, and then apply your edge weights.

10-26-2008, 03:17 PM
If you are going to be doing lots of mirror/symmetry work in LW you might want to look at Terry Ford's free mirror tools. Google that and you'll find him. I use them every day and they are a real help for modeling in symmetry.

10-26-2008, 04:40 PM
Should I use subpatch and not use Catumull Clark when making objects that I'll be mirroring?

How does Catmull Clark perform in regards to deformations, etc.?


10-26-2008, 11:26 PM
CC's look much nicer than subd's. But there are a few problems with it.

The main thing to remember about CC is that is subdivides with a different math than subpatch. In the very beginning of my tutorial I explain it. There are some pictures there too to help illustrate - courtesy of Been Vost.

So the setting of CC subdivision for display and render is exponentially higher than that for subds.

Using CCs has a few more gotchas when it comes to production than just this. For instance creating UV's don't work as well of if at all at times with CCs. Not sure if that has been fixed or not. Another problem I have heard mentioned is morphs. But I could be wrong. One thing for sure if you use CCs and are planning to do other aspects of production such as displacement and morphing, animation etc. You'll find out soon enough the various little glitches that are still there.

I never use edge weights. Ngons are nice. But I therefore only use CCs to check my model until my model is all quads. For me that was the one thing I was looking forward to with CC's, being able to just hit the tab key at any stage of my model and have it deform to check it.

If you ant do use them for modeling with edges do as HR says. That's about the best advice there.