Real-Time Physics Simulation Forum

Re: Mesh Loading

2011-03-13T23:26:44+00:00

It is being done by default my apologise!

If I partition the large mesh how likely is it that objects transitioning between the two Triangle Mesh shapes might collide when sliding over a seam? Would the heightfield array col shape be able to hack having a much larger triangle count in comparison?

Thanks for the great support on this issue Erwin I can get the ball rolling nicely with what I had before but this is a great boost to getting physics meshes in! I am looking to rotate and scale all objects loaded per bullet file by a set of rotations and then my physics data will be all set I am aware instancing is not possible so wont bother trying my hand at that.

Statistics: Posted by EnlightenedOne — Sun Mar 13, 2011 11:26 pm

Re: Mesh Loading

2011-03-13T16:57:58+00:00

It works, loaded in with the serialize demo no problem, do I need to convert it to btScaledBvhTriangleMesh now I have it loaded in? or is there a way to set this in Blender when using a static triangle mesh?

Great work! EO

Statistics: Posted by EnlightenedOne — Sun Mar 13, 2011 4:57 pm

Re: Mesh Loading

2011-03-13T16:41:28+00:00

downloading will keep you posted!

Statistics: Posted by EnlightenedOne — Sun Mar 13, 2011 4:41 pm

Re: Mesh Loading

2011-03-13T16:36:28+00:00

You need revision 2338 or later.

I just uploaded a new download for convenience. Normally you need to manually do a svn checkout, as explained here.

Does it work for you?
Thanks,
Erwin

Statistics: Posted by Erwin Coumans — Sun Mar 13, 2011 4:36 pm

Re: Mesh Loading

2011-03-13T15:54:45+00:00

I attempted to use the new blender method with trunk 2321 and failed "Unsupported shape type 22", warning file DNA is different than built in. The DNA of the file is newer than that which is built in. Therefore I figure that 2321 cannot be the right trunk version, however it looks like the latest trunk! can you clarify what version of the trunk I need to be using?

Statistics: Posted by EnlightenedOne — Sun Mar 13, 2011 3:54 pm

Re: Mesh Loading

2011-03-13T15:01:20+00:00

Thats excellent news, thank you for the full compile!

To clarify if I set a large mesh structure say a plane in the shape of a bowl (like the one below) as a "static" triangle mesh it will automatically be read in as a btScaledBvhTriangleMesh shape by trunk 2321 or greater?

This was added using a rewritten version of world importer from another thread so that a triangle mesh rigid body could be loaded from Blender properly although serializing it failed as this was not patched.

How dramatic would the difference be between a btScaledBvhTriangleMesh and a 0 mass rigid body in terms of speed of processing with a vast number of triangles? My 0 mass rigid body terrain struggles as the number of objects rolling on this massive shape increases. I am going to run some tests to see how big a speed boost I get between the old and new method but if you have any early words of wisdom for optimising such a huge structure (beside increasing the margin) I would be glad to hear it!

Also I am loading in a .bullet world per mesh on the initialisation of a scene as it allows for a mix of objects to be loaded independently into a world based on a users made script, are there any catches with doing this I need to be aware of?

Thank you for your excellent physics engine!

EnlightenedOne

Statistics: Posted by EnlightenedOne — Sun Mar 13, 2011 3:01 pm

Re: Mesh Loading

2011-03-12T21:04:09+00:00

From now on, you don't need a patched version of Blender anymore: Blender 2.56 trunk (revision 35500) onwards has .bullet export.

I uploaded a precompiled Windows 32bit binary of Blender here, with a sample .blend file that exports a .bullet
http://code.google.com/p/bullet-physics ... loads/list

You need the latest Bullet trunk version for the latest btBulletWorldImporter, with btScaledBvhTriangleMesh support.
Thanks,
Erwin

Statistics: Posted by Erwin Coumans — Sat Mar 12, 2011 9:04 pm

Re: Mesh Loading

2011-03-03T19:49:55+00:00

the zlib.dll was uploaded and Blender 2.5 will support .bullet exporting I have succeeded in exporting mesh files I am confident I can load them in!

Statistics: Posted by EnlightenedOne — Thu Mar 03, 2011 7:49 pm

Re: Mesh Loading

2011-03-01T22:41:43+00:00

Okay I have discovered that the patch is something you can not load as an update but if you drag into the preferences window it also loads into the main window and you can close the preferences window which repeatedely loads the scene and you have a version of the house being destroyed over and over. Now I just need to figure out how to use thats converting capabilities and I am back in the game.

I hope someone finds this thread and realises that the modified blender file is of absolutely no value you just have to force the patched scene to load into blender.

I will keep this thread posted on how I get on in the hope of it beind useful or at the very least eventually inspiring someone to write a tutorial which I might have to write when I have this figured out.

EO

Statistics: Posted by EnlightenedOne — Tue Mar 01, 2011 10:41 pm

Re: Mesh Loading

2011-03-01T18:42:41+00:00

I was able to get partial success by ignoring indicies because my mesh formats exporter is ancient but the triangle reading data fell apart 160 odd triangles into parsing a mesh throwing unreadable values into the mix which cannot have been an allignment problem, I am guessing it has something to do with only partial components of the single mesh object being indexed which I did not think was possible, I did get many triangles out but when trying to use it as a convex shape btQuantizedBvh.h started throwing errors at around line 355. This parsing becoming arbitrary and complex leaves me completely up a creek. The Blender version for exporting does not work 3DSMAX 2010 is not supported and I do not have access to Maya.

Can someone PLEASE FIX THE BLENDER BULLET EXPORTER BY PROVIDING THE MISSING DLLS! (above) SO I CAN LOAD IN .BULLET FILES! I have zero capacity to switch the entire engine out to Collada in time for my schedule and I am desperate to get a prototype of the physics running as soon as possible my scene has 3 meshes and I want to include a raycast vehicle.

Statistics: Posted by EnlightenedOne — Tue Mar 01, 2011 6:42 pm