Bullet 2.68 RC1: soft body preview (updated April 11)

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Erwin Coumans
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Bullet 2.68 RC1: soft body preview (updated April 11)

Post by Erwin Coumans » Tue Apr 08, 2008 3:07 am

Download Bullet 2.68 RC1 here: http://code.google.com/p/bullet/downloads/list

Changelist (and some soft body related improvements) will be in the final release, expected the early next week. Make sure to press ] in the soft body demo.
Feedback welcome,
Erwin

chunky
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Re: Bullet 2.68 beta2: soft body preview

Post by chunky » Tue Apr 08, 2008 4:01 pm

In the zip file I downloaded, bullet won't build in my project with the soft body stuff because btSoftBody::CreateFromConvexHull is declared and used [at the end of btSoftBodyHelpers::CreateEllipsoid] but never actually defined anywhere in src/. So it won't link if I just drop the library part of bullet, including SoftBody, into my code [which is how I currently use bullet]. By removing SoftBody/ from my project, I didn't suffer this linking error, but then I also don't get access to the SoftBody stuff.

It's actually defined in Demos/SoftDemo/SoftDemo.cpp, but it depends on ConvexHull. Obviously it's there because ConvexHull is part of Extras, and you don't want anything in src/ depending on anything in Extras/... except you're depending on something in Demos/ instead, probably even worse :-)

I would suggest that [assuming it's mature enough] ConvexHull just gets added to the main src/ directory and move the definition of btSoftBody::CreateFromConvexHull into btSoftBody.cpp, but I assume there's a reason it's still in Extras/ instead of in the main distribution, so, I dunno.

Gary (-;

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Re: Bullet 2.68 beta2: soft body preview

Post by chunky » Tue Apr 08, 2008 5:53 pm

Of course, what I failed to mention is that the soft body stuff looks freaking awesome. Great work :-D

Gary (-;

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Re: Bullet 2.68 beta2: soft body preview

Post by Erwin Coumans » Tue Apr 08, 2008 9:25 pm

ConvexHull is in the Extras folder, because its memory usage needs to be re-organized and using btAlignedAlloc rather then directly 'new'.

We will check what to do with ths btSoftBodyHelpers::CreateEllipsoid dependency on ConvexHull.

Note that the soft body is an early preview, things might change a lot in upcoming releases.
Thanks for pointing this out,
Erwin

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Re: Bullet 2.68 beta 3: soft body preview (updated April 10)

Post by Erwin Coumans » Thu Apr 10, 2008 11:13 pm

ConvexHull source has been refactored to use btAlignedAlloc/Free and moved into Bullet/src/LinearMath and Bullet/src/BulletCollision/CollisionShapes, so we removed the Extras/ConvexHull folder.

Latest Beta 3 also has premature soft body versus soft body interaction, use ] key to toggle between scenes.

Download Bullet 2.68 beta 3 from http://bullet.googlecode.com, or check out the Win32 binary demo (use ] key to switch demo) http://bulletphysics.com/BulletSoftBody.zip

Feedback is welcome,
Enjoy,
Erwin

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Re: Bullet 2.68 beta 3: soft body preview (updated April 10)

Post by chunky » Fri Apr 11, 2008 1:24 am

Works great now when I drop it into my project!

Thank-you very much,
Gary (-;

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Re: Bullet 2.68 RC1: soft body preview (updated April 11)

Post by goret » Mon Apr 14, 2008 12:42 am

Hei, fabulous, this soft body demo contains a lot of features !!
It looks to be really clean and efficiency, great job !!

I've just seen that only convex shapes are supported for collision detection against soft bodies, is there any plan for the concave one, or should I stop using compound shape in my software :) ?

thx !

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Re: Bullet 2.68 RC1: soft body preview (updated April 11)

Post by Nathanael » Mon Apr 14, 2008 2:04 am

goret wrote:I've just seen that only convex shapes are supported for collision detection against soft bodies, is there any plan for the concave one, or should I stop using compound shape in my software :) ?
Yes only convex shapes are supported for the moment, composites are work in progress, and trimeshs are planned for 2.69 .
If its urgent, you can to give it a try, look in BulletSoftBody/btSparseSDF::DistanceToShape .

Thanks, Nathanael.

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