Rigging very high density triangular meshes

Hi
I work at a pediatric hospital as a researcher. One of our projects is to reduce anesthesia duration of cancer patients. Basically, we work on treatment planning such that the kid’s tumor is placed in a 3D model and we position the model on the table in an optimum way to avoid unnecessary time. There is a database (http://lifesciencedb.jp/bp3d/?i=BP9115) and the model is a scanned body. We use skeleton and the skin. However, the mesh is not proper for rigging. Once I rig the model and manipulate the extremities, vertices do not behave well.

What would you suggest? How should I make the model proper for rigging? I spend so much time to correct vertices after the manipulation, but this is not that much useful. We want to make a free and easy algorithm using Blender, so other children’s hospitals can use it.

Any help will be appreciated a lot.

your model has too many vertexes to be rigged. try using the decimator modifier on it, then applying the modifier, and try it then.
(edit) this same thing happened to a guy recently when he tried to rig a dense mesh he had sculpted. as I recall it worked much better once he decimated it.

Once I rig the model and manipulate the extremities, vertices do not behave well.

Exactly what are you trying to rig / animate? You talk of skeleton, skin and as well as tumor. Sounds like there are lot of overlapping meshes all over the place. Method to use for some thing like that is to weigh the bones with Envelope. Did you do that?

Hi Modron
Can you give an idea how much should I decimate? I think if I know the order of magnitude of the number of meshes I can try it.

Thank you

Hi ridix
I try to rig and animate the skeleton and skin. However, skeleton is not an issue. The problem is the skin. Tumor is small compared to the model and just attached to skeleton, therefore it is also not a problem.
Because of the high number of meshes envelope is not a solution.

I would try to cut it down to about 20,000 polys, but it depends somewhat on how powerful your computer is. just make sure you keep the original file, and work on a copy, because you can’t undo a decimate operation.
(edit) you might also want to consider retopologizing a version, if you want a nice clean mesh. nice and clean is something the decimator modifier does not do very well.

Hi Modron
I think you are right about using retopologizing (which I just heart from you), because the model is not the best for rigging. It consists of triangulars. Also, the model doesn’t have a proper rest position, therefore the armpit is the worst place for manuplations (any suggestions?)
I will look into retopologizing now, do you have any suggestion, tutorial, sample?

Thank you

armpits always create problems. there is an add-on called ‘corrective shape keys’ which I highly recommend. the way it works, is, you pose your model so that you are getting the bad deformation, then you make a duplicate of it, which you then edit, to iron out the bad deformations, then, those vertex postions are applied to the original mesh as a shape key. after that, you can manually key those shape keys, or make a driver that is linked to the rotation of a bone, so it will do it automatically.
(edit) here’s a break-down of the retopo process:
place your vertex, or vertexes in front of your model, then press the button on the main header that looks like a magnet.
In the options to the immediate right of that button, set it to ‘face’.
more buttons will now appear just to the right. press the one that looks like a square in front of a circle.
you can retopo at this point. if you move the vertexes, they will snap to the model surface underneath.
but in order to see things better, you should go into object buttons >> display settings >> x-ray
then, in your 3D window, while in edit mode, press N for a whole new set of buttons, and find the one that says ‘hidden wire’ in the shading panel.