OBJ import vertex normals

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zpaolo
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Joined: Wed Feb 09, 2011 2:40 pm

OBJ import vertex normals

Post by zpaolo »

I googled this up but could not find a solution... when importing an OBJ file it looks like vertex normals are not imported correctly. The model looks "faceted" and not smooth. In Lightwave when importing OBJ models (generated by Pro|Engineer) each surface has a vertex normal map attached that can be enabled to "smooth" the facets where needed. Am I missing something? Maybe I just can't find where to activate vertex normal maps in Blender 2.5...

Paolo

CaveMole
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Joined: Wed Oct 11, 2006 3:32 am

Re: OBJ import vertex normals

Post by CaveMole »

Same problem. any response yet?

killpotts
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Joined: Sat Jun 20, 2009 7:04 am

Post by killpotts »

Blender uses edgesplit to fake normals. It does not support edge normals and never will because the community is content with blender being incompatible with other programs way of doing things. I highly disagree with this general consensus and feel that a lack of the more widely used normal support is a huge flaw in Blenders design.

The saddest part is that the UI is already there. You Actually can go into edge/vertex mode and shade smooth/flat. It just doesn't work or do anything unless you are in face mode which defeats the entire purpose.This bug has existed for years. Sigh...such a tease.

Worse, other basic free programs for CG like Wings 3D support edge smoothing. It's only Blender that thinks it can get away with it not having it because of edgesplit. Not that edgsplit and sharp edges don't work, they do...the problem is that edgesplit only works on export and it dupes your vertices which not all other programs support.

Blenders current smoothing system is designed to only do the job well if you keep all your work in Blender. If you are constantly exporting/importing OBJ files for a group project then Blender is destined to fail at smoothing.


If you absolutely MUST use Blender for projects such as this due to licensing costs associated with alternatives, the best way to do it is to download Wings 3D and use it as a mediator between Blender and other programs. Wings is not as good as Blender in most all other regards, but it supports edge normals.

Don't get me wrong, this is not a Blender bashing rant. Blender is a great 3D modelling and animation package and I use it frequently for certain tasks over 3DSMax and Maya which I hold licenses for. But Blender does have some quirks in it and this IMO is by far one of it's biggest.

At least, I think this is what you are talking about.

If you are talking about face/flip normals and not smoothing normals then all you have to do is press CTRL+N and recalculate.

zpaolo
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Joined: Wed Feb 09, 2011 2:40 pm

Post by zpaolo »

killpotts wrote: At least, I think this is what you are talking about.

If you are talking about face/flip normals and not smoothing normals then all you have to do is press CTRL+N and recalculate.
That was exactly what I was talking about, smoothing normals. Too bad they are not compatible with Blender, I'll have to use something else :)

Thank you anyway for the answer

Paolo

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