Hi there, I'm struggling to succesfully export a model from the XSI mod tool with a skeleton.  When I try and import it I get an error namely "Error normalizing vertex bone weights. BoneWeightCollection does not contain any weighting values."

I was hoping if someone could tell me if I'm just missing a small step somewhere or if my error is more grave.  I'll go through the process briefly and perhaps someone could enlighten me if they spot a misstep. 

As a test I'm trying to create a three boned model, like a finger, consisting of three cubes.  I begin by creating a basic cube.  I duplicate and translate it twice to create a small tower.  I then freeze all the transforms on these objects to clear the operator stack.  I select all three cubes and in the 'Model' panel I go to 'Create -> Model -> new Model'  The result looks like this...

I then change to the 'Animate' panel and start to create the bones.  In the 'Animate' panel I change the construction mode at the bottom left to Animation.  Then I go to 'Create->Skeleton->draw 2d chain' and proceed to create three bones through the centre axis of the cubes.
 

I then select the bottom cube and and weight it to the bottom bone.  I do this by selecting the cube, going to 'Deform->Envelope->set envelope' and 'pick' the bottom bone.  When the property editor pops up I leave it at the default values namely "number of skeleton object = 2".   I repeat this two more times for the remaining two cubes and bones.  The result in XSI is that I have three connected bones that will move the cubes around like a finger as intended.



I can keyframe and animate these bones in XSI and it works as I expect it to.  Finally I go to 'File->Export->DirectX export'  and save the file again with the defualt values.  When I import the directx model into XNA is brings up the error message "BoneWeightCollection does not contain any weighting values" as mentioned above.  I tried a couple of things like creating the bones first before selecting 'Model-> new Model' but to no success. 

If anyone could perhaps fill in a step or process that I need to do I would appreciate it. 

Thank you, Richard.

Well I haven't really played around with skeletal animation much myself yet, but you might try creating a weight map inside the Mod Tool before exporting. If you want each box to be affected only by one bone, then you can weight the verts of that box to 100% for that bone. However, you can also have verts that are partially weighted to two different connected bones, which allows the verts to deform as the bones are bent, like the wrinkle at the bend of a finger.

Thank you for the reply.  Unless I am mistaken I  create the weightings for the vertices when performing the 'set envelope' operation and picking one of the bones.  It certainly seems to function that way inside of XSI. 

I had another think and read about it and it the same way you need to freeze the operator stack when modeling, I think I need to freeze the envelope weights as a final step.  I did so by selecting the whole model, including the bones, opening the weight panel and clicking on freeze weights. 

Upon exporting again the same error came up, "Bone weight collection does not contain any weight values".  I'm sure it's a small step I'm missing somewhere and hopefully I'll work it out eventually.

Richard

Well as I said, I don't have any personal experience yet with exporting animation. I searched Google for your error message and I got two hits. Neither of them talk specifically about the XSI Mod Tool, but they both say that this could be caused by having some vertices which are not assigned to any bone. If that doesn't help, I don't know what to tell you... sorry. Anyway here are the links:

http://forums.microsoft.com/MSDN/ShowPost.aspx?PostID=1195526&SiteID=1

http://www.codeplex.com/animationcomponents/Thread/View.aspx?ThreadId=8491