Can Bullet Be Used for More?

I am spending the day using Bullet physics to distribute thousands of alpha mapped plant polys over a landscape. I wish that Bullet physics could be used via the particle generators. My method is first to setup Bullet physics on an object then turn it into a particle object. I further randomize the duplicate particles then I make the meshes “Real”. Then I drop the landscape objects onto the ground plane. This method works great but it’s so sloooooooooow.

I wonder, can Bullet physics can be used for more and get a bit faster with large numbers of meshes?

Thanks for using Bullet!

  1. Some physics tips here:

  2. Choice of collidion bounds type matters: performance for box,sphere, cylinder, cone and convex hull is much better then static triangle meshes.

  3. Bullet-Blender specific questions can best be posted on my forum, otherwise they might not reach me:
    Perhaps post a topic there, and upload a .blend (sorry, registration might take some days, too many spammers…)

  4. There are more plans for Bullet within ‘regular’ blender (rather then just game engine):

And one more interesting pdf tutorial:


Thanks for using Bullet!

Do you get a warm and cuddly feeling inside when people use and compliment how good your work is?

Thanks Erwin! And thanks for the links! Bullet is amazing. I had to stifle myself as I was kinda getting outa hand throwing crazy poly counts at Bullet physics. I almost lost a good scene setup.

I’m looking forward to trying out the new Bullet updates. It looks like the days of hand placing shrubs and rocks over a terrain are over. Sweet. It’s so cool to set all of the objects up with Bullet physics and just “drop em’ like their hot”. Hehehe. Based on dampening, etc., objects float down and conform to the landscape. Rocks roll into their final resting places.

Is there a way to make one object work like a magnet and attract objects that will stick to it’s surface?

That’s a cool approach, but you could have used the script that distributes objects over an area, randomizes their scale and rotations, then drops them onto the ground mesh. It will also orient the cards to face the camera for you. Courtesy of me and Jimmy Haze. Very fast and easy…

Harkyman I could hardly create organic looking landscapes without your scripts. I have not gotten the drop script to work right for me yet. When I use it one of the objects will drop but the others stay put. I know I probably missed some crucial setting and was rushing too fast through a project to get it right. The card orientation works great. Thanks man.

The reason why I started using Bullet physics was that I needed more accurate placement for my objects. I’m only three day into using Bullet physics and it’s so easy to use. How many of 3d artist use the cg physics in our work? I never used physics for any of my design work until now. I would manually place each object or just use an array or particles. Physics are so much more accurate for this kind of work.

I was recently searching Cgtalk for tips on how to more accurately place huge groups of polys on a mesh surface. Maya’s tools seemed to be the best at doing this. Maya lets you paint mesh objects onto a mesh surface. I don’t use Maya so I had to find another solution. The beta build Blender 2.42 had the perfect solution for now with Bullet physics.

Oh yeah, If you use the Bullet physics method that I described earlier make sure that you keep your mesh count at around 40,000 polys per bake. Otherwise, “Crashola”, hehehe… Set your animation keyframe end to 2000+. Turn off your screen saver and wait for each physics solution to bake. You have to manually stop the solution with the Ecs key so be careful. It takes about 20min or so for dense groups of polys. You can grab a handful of polys that have the Bullet physics delete what you don’t need. Using different scenes you can bake polys to only the used sections of your ground mesh. After that you use the “Apply Deform” script to set the polys and drop the IPO’s. Then link these scene sections baked polys to one scene and feel the love, hehehe. Yeah!

The possibilities with Bullet physics seem endless.

Blend on!