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Joey_C
02-08-2015, 05:42 AM
Bullet Dynamics have worked great for me if my geometry is over 1m.

It is not working well for me with geometry 500um.

Are there any tips I need to know?

I can do anything with a mesh 1m or larger but nothing with a mesh 500um.

THANK YOU very much for your help. New at Bullet.

prometheus
02-08-2015, 06:45 AM
Bullet Dynamics have worked great for me if my geometry is over 1m.

It is not working well for me with geometry 500um.

Are there any tips I need to know?

I can do anything with a mesh 1m or larger but nothing with a mesh 500um.

THANK YOU very much for your help. New at Bullet.

Check the manual, bullet do not work well with such scale dimensions.

prometheus
02-08-2015, 06:53 AM
you could sign up for lightwave 2015 trial and also get the enhanced pdf manual which will be available in your account after you download the trial..
bullet is documented in older pdf as well, but I am not sure exactly in which one of them, you need to find out when bullet was implemented and find that designated pdf manual for that version.

hereīs an excerpt....
In order to ensure dynamics calculations are free of problems, it is worth noting these guidelines:
• Make your models not too small, or too large, as Bullet gives more predicable results when
working with objects sized roughly between 0.4 - 10 m.
• Any collision objects such as ground planes should not be infinitely thin, but have some
thickness.
• Objects made of triangles and quads will generally behave better.
• When using the built-in shapes within Bullet, have some Collision Margin set. 5mm is a good
default.
• Bullet doesn’t work with negative frame numbers.
• Prepare your objects for dynamics, ensuring:
• Models are ‘air-tight’, meaning all points are merged and there are no un-modeled holes
in your mesh (missing polygons).
• All single points, and 2-point poly chains are removed.
• Objects don’t have extremely long, thin polygons.

Joey_C
02-08-2015, 09:38 AM
THANK YOU VERY MUCH!!!!! Maybe you would have a recommendation. Pretend you have a power pole sticking up out of the ground holding power cables up and there is a model toy airplane that's flying straight by and just nips the side of the power pole and bounces of coarse. What FX would be best to get that effect?

prometheus
02-08-2015, 10:10 AM
THANK YOU VERY MUCH!!!!! Maybe you would have a recommendation. Pretend you have a power pole sticking up out of the ground holding power cables up and there is a model toy airplane that's flying straight by and just nips the side of the power pole and bounces of coarse. What FX would be best to get that effect?

Not sure, having moving vehicles and especially aeroplanes in bullet simulation dynamics can be tricky..parenting a dynamic object like an earoplane to a master null and only affecting the body of the plane is tricky, and just using the airplane with bullet dynamics are tricky too.

But I am not exactly sure of how you want the effect?
should the airplane bounce? and should it have some of itīs own body pieces destroyed, or will it just bounce and change rotation and direction?
or is it mainly the power cables that will move and bounce? or both the plane and the power cables?

I have tried a little with some airplane effects and hitting stuff, but I am not there yet ..it involved having the airplane moving in proper direction and also getting wings destroyed when hitting a rock or building, I have found bullet not so easy to
work with on that, might be easier to keyframe animation only and skip trying to get realistic behavior through bullet.

You can also try old dynamics..theres a good free (previously commercial) tutorial dealing with an airplane hitting power cords and a little similar to what you might need, maybe not exactly..but it will give you some fondation on the old system.
You can probably adapt some of it to work with bullet instead, cables can be made with 2 point polychains, and the cable geometry is linked by metalinking, you can either use old dynamic soft system or bullet softbody for it.


Greg Sullivan showcasing technical direction...



https://www.youtube.com/watch?v=wDvLVsYTEaA


Edit...I donīt know it the new bullet motor system in lightwave 2015 may help to simulate aeroplanes, it might...you can at least simulate good car movements and such.

Joey_C
02-08-2015, 02:00 PM
You have been so helpful THANK YOU very much!!!

prometheus
02-08-2015, 02:06 PM
Glad to be of service, good luck, and never be afraid to ask questions.

Michael

prometheus
02-08-2015, 03:17 PM
I was actually linking the wrong tutorial.though the other one fits in well too.
this is the one you might look at...


https://www.youtube.com/watch?v=-xTKd7pA3rU