Preamble:

A have searched the forums for a potential answer without luck, so here I am with a very basic question. Believe me, I won't be bothering you for such a simple thing, but after countless hours trying and trying ... better to ask anyways.

The issue is:

I am doing a simple cube in Softimage Mod Tool 7.5 and then exporting it using the fbx format. When rendered in a XNA window, this simple cube looks pretty weird. I know what is happening: model normals have been “averaged” to provide a sensation of smoothness. This would be quite nice in a round model and is desirable in many cases, but not for this model (yeah, a simple cube for testing). I have tried any possible thing into Softimage to fix the normals and nothing seems to work.

If I export using directx format, model comes fine, with sharp edges. Inspecting both fbx and direct files, what I was thinking was confirmed: while directx assign values of 0, 1 or -1 to all normals, fbx assign numbers higher than -1 and lower than 1, creating the “smooth” effect in edges and faces.

I want to keep exporting in fbx. Any advice on how to fix this into Softimage? I really don’t want to write a custom importer just to fix bad normals if is avoidable through the software itself.

I am using Crosswalk 4. Same issue when using version 3.3. The fbx exporter works fine in Max and Maya, so I am guessing is something I am missing in Softimage.

Thanks in advance.

Oooh weird!

As far as I know, XSI doesn't have any smoothing groups or anything like that, hard creases like on a box should always look pretty hard.   The only way to make edges smoother/harder is to pick the model, go into render->property->geo approximation then mess with the discontinuity angle in Polygon Mesh tab.

Picking the box Freezing all transforms after bringing it in might change its shading too. (Right click transform->freeze all transformations on the right)  Or um, ctrl-a, then Freeze at the bottom right.

Hi If-Laser, I did Freeze all tranforms before exporting. Further exploring the exported file bring some light on this.

What I did was to ask a friend to export the same model from another application: 3ds max 2009. He used exporter that came with the max intall and has not updated to the new version. Anyways, exploring the files I noticed a chunk that explain the issue:

When exporting from Mod Tool 7.5, Crosswalk 4.0, the part that cares of polygons and their normals has this piece:


While the max counterpart for the exact same model has this one:

You can notice a few key diferences: first off, MappingInformationType. Is taged as ByVertice on XSI while is ByPolygonVertex on max. The other obvius thing is the normals themselves. Values greater than -1 and lower than 1 in XSI, while exactly -1, 0 or 1 in max.

Is there any way to control this from XSI or I have to live with this workflow and correct the normals on the way?

I'm experiencing the same problem with Modtool normals - and it is mentioned here:

Hi Eclectus,

Thanks a lot for those links and for providing more info on this issue. I'll try Mod Tool 7.5 "Export XSI Normals" option at home later. I remember checking that (on or off) and nothing happened. I'll give it another try anyways, and hope tomorrow I'll come with some good news.

I really hope this works, as I definitely will not have XSI 2010 (nor 7.5) at hand ... just the fantastic (and free) Mod Tool at the moment. Of course I can download the trials but they last 30 days and is for sure I'll be doing some model longer.

Just for the record: the values asigned by Mod Tool 7.5 (or better said, the Crosswalk 4.0 fbx exporter) at every normal is  sqrt(3)/3, of course signed as needed.

Hmmm, Why is that?. Another question here.

Hi all,

I had another look at fbx exporter and no “Export XSI Normals”  there (Crosswalk 4.0, Mod Tool 7.5).

I’ll see what can I do to fix this by my own … I’m guessing a custom importer may worth, the only thing is how to get the polygon smoothing information out of XSI and into the fbx file, as some polygons may have hard edges while others not in the same mesh.

I really love and appreciate mod Tools developers who bring us such a wonderful tool. Really a top notch 3D application. I’m wondering how they miss this issue. I would really love to focus on coding and modeling but hey, a new challenge is always welcome!

If I come with something useful for the community on this, I’ll get back and share whatsoever I found/do

Hi Cosmos - thanks for your replies.