Blender is one program I just don't get. 3ds Max, I get (just barely), but when I open Blender I feel like a monkey trying to figure out a math problem. Hats off to anyone that does get it, they produce some really cool stuff and I am a little envious.

Blender is not that much harder to learn than a lot of other software once you know the GUI "philosphy", work through a few tutorials and you´ll quickly get the hang of it.

Actually, I don't use Blender for modeling, but I think too that GUI Blender is "non-conventional" but not difficult.

For me is like WordPerfect 5.1. When finally you learned all the keys and combinations, it was powerful and quiclky. (Ok....the 3 first months I wanted to fire to WP51 developers) :-)

I didn't know that Blender didn't import the OBJ files properly.

I remember that someone in the forum created a script for import the MoI models in LWO format, but I haven't try those script in Blender 2.5.

http://moi3d.com/forum/discussion.php?webtag=MOI&right=search

< I didn't know that Blender didn't import the OBJ files properly.
If there any problem just ask to developpers to make something for that!
maybe there
http://code.blender.org/index.php/about/

Hi David,

> I didn't know that Blender didn't import the OBJ files properly.

Yeah, it may not be something that you'd notice on certain models, because all the polygon faces do come in - it's the stored vertex normals that should be used for shading those polygons that don't come in.


> I remember that someone in the forum created a script
> for import the MoI models in LWO format, but I haven't
> try those script in Blender 2.5.

I did a quick try of them and they didn't seem to work anymore, I think the script API has changed.

Here is the original post on that:
http://moi3d.com/forum/index.php?webtag=MOI&msg=979.1

Also Anthony who did that Blender LWO import script has a custom build of an earlier version of Blender 2.5 here:
http://moi3d.com/forum/index.php?webtag=MOI&msg=3583.1

However, that build is pretty old now.

In addition to just importing the normals Blender also has a problem that it discards any existing vertex normals when you do a rendering or go into polygon edit mode, that has some bad side effects like not being able to edit UV coordinates without having the normals discarded and recalculated. That custom build avoids that.

- Michael

Hi Pilou,

> If there any problem just ask to developpers to make something
> for that! maybe there

Well, it seems that some of this behavior has already been reported as a bug.

For example here is a recent bug report that someone submitted about normals changing just when entering/exiting edit mode without doing anything else:
http://projects.blender.org/tracker/?group_id=9&atid=498&func=detail&aid=26405

Unfortunately the Blender dev says that they don't intend to fix it anytime soon and the bug report was rejected and closed.

- Michael

Yeah, Blender gave me a headache when I was trying to learn it :P

Ended up choosing Modo (mostly just for rendering, but also for smooth or organic shapes).

I'm just so glad I have MoI to model in <3

@Michael
Ok I will say that to a French guy who has some entry with the Blender Team and developpers ;)

Then, the best method for export is:

MoI-->export LWO-->Import LWO with Anthony's script in 2.49& save-->open *.blend file in 2.5

isn't it?

So with the lwo method, there is no problem of Normal?

Ah, I remember the times when Ton Rosendaal himself would bring his kid to the CeBit in Hannover, and drop by at our booth for a small CAD software (non-existent in today´s market) and you´d have time for a chat. Those were the days, already a powerful application.

Hi David,

> MoI-->export LWO-->Import LWO with Anthony's
> script in 2.49& save-->open *.blend file in 2.5
>
> isn't it?

Yeah, that would seem to be the only way to load the normals into 2.5 right now.

But unfortunately you'll still run into some problems if you then render, or try to edit UVs because both of those actions throw out any existing vertex normals and recalculate them by averaging polygon face normals.

So just loading them in is only part of the whole problem...

Blender just does not in general treat the vertex normals as an important channel of information that should be preserved when possible. I mean you do have to recalculate normals if you move some 3D vertex locations around, because you're then changing the shape of the model and it needs to be shaded differently to represent the new shape. But if you're just going to edit UV coordinates or do a rendering there is no reason to throw them out.

- Michael

There is not this problem with other progs like modo c4d ...?

Hi Pilou,

> There is not this problem with other progs like modo c4d ...?

No, it's not a problem with other rendering programs - both Modo and Cinema4D for example will load vertex normals from a file and then be able to use those vertex normals for shading when rendering.

Blender is pretty unique in just ignoring them, and it's especially unique when it comes to rendering - when it renders it ignores any existing vertex normals and recalculates some new ones just for the render. This is pretty weird because it makes the render look different than what is actually present in the model data and from what is being displayed in the realtime view (when you may have managed to get normals loaded in the first place).

Unfortunately this makes rendering many kinds of CAD data pretty difficult with Blender, because it is important with CAD data to make use of the normals that come from the original surfaces.

So anyway in this area of getting high quality shading from CAD data, Blender is far far behind pretty much every other rendering program out there because of this.

- Michael

But also - these issues were fixed for Blender 2.49 with Anthony's work.

He implemented an importer that would load the vertex normals in (forum thread here), and also at one point made a custom Blender build that would not throw away the normals for rendering (forum thread here).

However, the old import script does not work anymore with the new Blender version, and the patched version is an older version.

So those previous workarounds do not really help for the latest Blender release.

It's just too bad that it's not fixed up directly in the main Blender version instead of needing workarounds in the first place...

- Michael

>> There is not this problem with other progs like modo c4d ...?

> No, it's not a problem with other rendering programs - both Modo and Cinema4D for example will load vertex normals from a file and then be able to use those vertex normals for shading when rendering.

Do Modo and C4D have problems when a mesh is edited (or at other times)? In other words, are there times when Modo or C4D recalculate vertex normals and you end up with a bad model once again?

Hi YHWH_777,

> Do Modo and C4D have problems when a mesh is
> edited (or at other times)?

Yeah there are a few quirks here that could still use some tuning in Modo, like if you're in vertex mode and transform all vertices the vertex normals do not get transformed in that case. So you kind of need to watch out how you're transforming your object and transform it in "item mode" where the entire object is handled as one piece.

But just loading a file and then rendering it is fine.

There's a pretty huge difference though between having things get messed up in some particular circumstance that is avoidable, versus having no way to have things get shaded properly at all which is the case in Blender right now.


It is expected that if you yank some individual points around, that the vertex normals should then be recalculated - the vertex normals control how shading is applied to your object so it is tied to the shape of the object. If you pull some points around and change its shape, then that's when it does make sense for the normals to be discarded and recalculated because you don't want the new shape to have the old shading.

But pretty much anything other than that should keep the vertex normals intact.


- Michael

Maybe something here
http://blenderartists.org/forum/showthread.php?182195-OBJ-import-normals

Hi Pilou, yup that discussion thread is talking about this exact problem.

Anthony says in that thread there that he sent the patch to some Blender devs but that they did not decide to include it into the regular Blender build I guess? That's too bad...

- Michael