Using the blender game engine for a test bed

Hey there

I was hoping of using some software to trial physics, with the lack of choice in terms of physics simualtions, I chose to look into the nblender game enigne.

The physics trials would include stuff like this

The problem is, is that this was created in autodesk inventor, which costs a lot of money, a similar program is solidworks, which also costs a lot of money.

So I was looking for a low-cost alternative, when I came across the blender game enigne, which looks interesting, but I wanted to know, would it do the job and how would I go about it?

I know from experience that getting those sort of things stable in an actual simulation is very very complicated. If there is any way to not simulate it and instead fake it, I suggest you to do that.
Otherwise, there is just one thing you can do: Try it out, get your hands dirty and tweak every single parameter you can find.

Maybe increasing the physic steps and substeps could allow you to make such things, but then again, its as Dantus said: You have to try in order to really know.

I guess, it’s just it’s a big step to make from just plain modelling to actually putting in the time and effort (mostly time as it’s very constricted) to try to learn python just to find out that it’s not suitable, since that’s what I’d probabily have to learn in order to form the test bed.

I wanted to present to you my objective, and let people who are experianced with the game engine to tell me if it is possible to do what I want to do what I am aiming to do.

Sure, I accept that there are going to be limitations on what can and can’t be simulated, but those would be ironed out in the future, or perhaps something that can be achieved in a slightly different and perhaps a better way.

Yes. Here a demo made in 5 mins to help you start. Unoptimized. No python. Play and press ‘up’ cursor to spin the gear.

mzSimpleGearsDemo.blend (110 KB)

The BGE is great for making things (physics) look really cool. You can use Bullet or do everything with static objects and script from your college math and physics texts. But however you do it, it will always be fake. Even the most sophisticated software used by Boeing or NASA is fake. They always have to trial in the real world. But of course the sims usually give them a reasonable prototype with which to do real world testing.

Sure, something like a wheelbarrow might be confidently built straight from Blender. But even with NASA software you could not expect to design and sell a trebuchet without building prototypes and doing a lot of testing and tweaking in the real world.

Just checked out the blend and found the up arrow to run it. And your gears are rigid bodies, triangle collision mesh and set to default damping. Looks great. But what if you had a train of many gears, different sizes, different teeth shape, different materials. Would you be able to run a shaft of a particular diameter from gear six that would raise 100kg from the floor?

Over the decades engineers have been learning in the real world and then putting their specialized knowledge and experience back into sims but with caveats. It’s of some use to students and engineers who are personally consulting with peers and making use of trusted knowledge.

not sure if bullet can do this, but blenders single precision will be an issue as well.

theres a reason engineering programs are expensive. to me it looks like bullet is optimized for speed over accuracy.

even if you could get something close, i wouldnt trust any scientific data with it.

What do you want to achieve with the physics simulation?

The game engines focus is entertainment. This means plausible behavior is good enough.

The things you want to simulate are very very easy to present via a predefined animation (no physics at all).

Using the physics engine is sometimes possible (see the gears demo), but does not necessary deliver the results you are expecting. Beside of that it costs a lot of processing power and a lot of time tweaking the setup. The results are rarely transferable to real world.


As Monster mentioned, the game engine was primarily designed for entertainment and not for an actual physics testing which would be desirable, and at some point prototype testing would need to be done prior to the finial design.

For now, I plan to test basic concepts to see if they would work in theory.

Thank you for replying.

Hi BenDragon1337

there is a blender fork for cad
“Welcome to the official website of mechanical blender
a fork of Blender focused on cad utils developement.”

it seem you don’t need real time interactivity
so drivers are very powerfull in blender (not bge or upbge)

you can emulate drivers in bge by python scripts

some links :
Blender:Using Drivers to control tank tracks

blender tutorial: SpurGears

The physics law in game engine are “fake law” see : gleb alexandrov tuto …

hmm, interesting, thank you.