View Full Version : Help, The Normals won't behave!

02-12-2009, 10:57 AM
I just recently bought Lightwave 9.6 to make some high quality renders of some CAD models. However, when I import the OBJ files into Lightwave the normals are totally messed up. Some are flipped, some don't point the right way, and others are completely invisible even if flipped. I have tried all of the things I can find on fixing normals, like "Unifying Normals", but am still having the same problem. In fact unifying normals just flips each poly the opposite direction from what it first imported as. I have also sub divided the model as much as possible before exporting it and only get a lot more polys with the same issues. I have even hand flipped each poly on some models with only small problems, but when I bring the fixed model into Layout the flipped polys are now flipped again.

I can bring the same OBJ into Carrara 6.2 with only one problem, it triangulates the model to a ridiculous number of polys. (Which is why I no longer use Carrara.) I can export that model back to OBJ and bring it into Lightwave and the normals problem is gone but now the smoothing function can't seem to smooth out the excessively fragmented model.

Is there a better way or a piece of software out there to handle OBJ files from CAD better.

Can someone please help me here?:help:

02-12-2009, 12:08 PM
Hi Drakonsden,
You could try AccuTrans found here: http://www.micromouse.ca/
This will transfer many different CAD formats to LWO and back again and you can use it fully unlocked with no restrictions for 30 days. If you find it suits your needs then pay the very small fee to keep it.

02-12-2009, 03:40 PM
Hi Drakonsden,

If you have questions email me directly at micromouse at accesscomm.ca

If you have a small OBJ file that illustrates the problem you are having, you can email that also.


02-14-2009, 05:49 PM
Thanks Kosmodave and MicroMouse that is exactly what I needed.

02-14-2009, 06:02 PM
Is there a better way or a piece of software out there to handle OBJ files from CAD better.

Maybe this is what you need?

02-16-2009, 10:40 AM

That looks very good. The sample pictures are exactly what I am having problems with after I use Accutrans. Holes put into the side of round items get a very faceted look that cannot be smoothed out. Don't get me wrong, Accutrans fixed the severe randomness of the normals problem I was originally having, but I am now getting unsightly faceting.

How does TrueOBJImport handle sharp edged holes in the side of round items. The sample pictures show rounded edges on the hole. All of my models I am trying to import are of items that have ground sharp edges. The faceting takes away from the smoothness of the ground surfaces.

02-16-2009, 11:57 AM
Have you checked to see if the OBJ import has brought in a vertex normal map? You should see it in the surface basic panel.

As for the aligned faces there are a few progressive align tools. I think one if built in now called unify normals. If that doesn't work. There should be able to other tools on www.flay.com

02-16-2009, 01:10 PM

Can you email one of your OBJ files to micromouse @ accesscomm.ca and I will check it out and see what can be done to help you out with your problems?


02-16-2009, 01:45 PM
How does TrueOBJImport handle sharp edged holes in the side of round items.

It reads normal map stored in OBJ file as "vn" lines (see in text editor whether your have such commands). And it works with Fprime, mine own renderer/previewer and Kray, because it has node which is reading normals.