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My home-brewed bicycle
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3DRaddict Offline
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Post: #1
My home-brewed bicycle
I'm at it again (can't keep a good man down! wink ). This time my 80% engineering self is taking over, and the 20% artist is taking a backseat. Using some bits and pieces that I've collected over the years, together with my new JointHelper object and the Esenthel World Editor I've assembled a physics-based bicycle. The main jointed parts were pre-assembled in my favourite 3D modeller, and then transferred to the Esenthel Object Editor where they were given materials, physbodies and physical properties. These parts were then transferred to the Esenthel World Editor, ready for final assembly with joints:-

[Image: allparts.jpg]

Using my JointHelper I set up all the joints and positioned them carefully at there crucial locations... to end up like so:-

[Image: assembled.jpg]

Here's a short video clip of the bicycle initially standing, but very soon to topple over, as no real bicycle can stand unassisted for too long! It has to be moving forward to stay upright... but this is my next fun challenge! grin





As an aside, I must add that after getting more to grips with the slightly unconventional Esenthel toolset, I am now really appreciating its ease of use and the amount of careful thought and planning that has been put in by the Esenthel developer, Gregory.

A final word to the adventurous...
If you are attempting something like this then
1) Keep your dynamic physbodies simple and made up from standard primitives. Do not attempt to use convex bodies... these tend to end up unbalanced.
2) It is important that all parts are positioned accurately... do not guess... use numerically entered values in the World Editor popup dialog window.
3) Very important... ensure your jointed parts ignore collisions between them. For this, there is a boolean parameter in the CreateJoint functions. Other parts of your model which may collide with each other (unless by design) should use the 'actor.ignore()' function.
4) I've always used Kg/m3 for my material densities (seeing as PhysX use the MKS (meter, kilogram, sec) system). But I see that most users use densities expressed in gm/cm3 (I've failed to understand why). This means that the density of water is 1000Kg/m3 ( 1gm/cm3)
5) I'm used to scaling up the size of my physbodies, as I've discovered that PhysX does not take too kindly to physbodies less the 50cm in size. Gravity should also be scaled up proportionally.

These are just a few pointers that I've picked up along the way, to partially avoid jittering and exploding models due to instability issues.
05-12-2015 05:15 PM
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Pixel Perfect Offline
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Post: #2
RE: My home-brewed bicycle
Stunning! Can't wait to see this in motion, good luck with that smile
05-12-2015 06:15 PM
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3DRaddict Offline
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Post: #3
RE: My home-brewed bicycle
Thanks. I can't wait either!

I'm used to using PhysX with small tabletop models, and I've found that to avoid instabilities I've had to greatly increase my scale. So through force of habit I did the same for the bicycle. However, I've now realised that this bicycle is going to operate in the real Esenthel world of 1metre=1unit, and I certainly did not want to start scaling everything up to suit the bicycle's scale. So I've rescaled the bicycle down to Esenthel size.

[Image: toscale.jpg]

'TestCrashDummy' (the testrider-to-be) is of average height, 1.7m
Also, in the pic I've left the JointHelpers visible so folk can see the location and orientation of the joints.
05-14-2015 12:02 PM
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3DRaddict Offline
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Post: #4
RE: My home-brewed bicycle
Just completed testing that all the hinge joints are operating smoothly and correctly. No wheel contact with the ground at this stage.
I'm using the recently added "hingeDrive()" functions.



05-16-2015 08:47 PM
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RedOcktober Offline
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Post: #5
RE: My home-brewed bicycle
NIIICE...

--Mike
05-17-2015 12:44 AM
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Zervox Offline
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Post: #6
RE: My home-brewed bicycle
So, how long till mass production? wink
05-17-2015 01:06 AM
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3DRaddict Offline
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Post: #7
RE: My home-brewed bicycle
Mass production only on successful completion of test trials using "CrashTestDummy" to provide the pedal power on varying terrains. wink
05-17-2015 06:39 AM
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Zervox Offline
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Post: #8
RE: My home-brewed bicycle
Connect a ragdoll actor to it and away you go. grin
(This post was last modified: 05-17-2015 08:40 AM by Zervox.)
05-17-2015 08:40 AM
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3DRaddict Offline
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Post: #9
RE: My home-brewed bicycle
That's more or less my plan... just got to figure out the connecting part
05-17-2015 08:59 AM
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Zervox Offline
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Post: #10
RE: My home-brewed bicycle
Yeah, you sort of wish you'd have full body locomotion system(just to try out tech). smile anyways really interesting to see the fully physics enabled bike. smile
05-17-2015 09:02 AM
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RedOcktober Offline
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Post: #11
RE: My home-brewed bicycle
oh no... no, no, no, no, no Allan smile you're just nearing the end of the first half of this equation...

your next task is to create a self balancing controller (bike rider) who will become the controlling force and provide power to the pedals, and keep the bike from tipping over while it's in motion...

straight line biking will suffice for now smile smile

--Mike
(This post was last modified: 05-17-2015 02:18 PM by RedOcktober.)
05-17-2015 02:18 PM
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3DRaddict Offline
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Post: #12
RE: My home-brewed bicycle
You got that to a T, Mike grin
05-17-2015 02:28 PM
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Pixel Perfect Offline
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Post: #13
RE: My home-brewed bicycle
after all ... those surfing dudes are going to need some form of transport to get down to the beach wink
05-18-2015 12:03 PM
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3DRaddict Offline
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Post: #14
RE: My home-brewed bicycle
My bicycle now has a 'rider' to provide some peddle power. Still suspended above ground, but 'CrashTestDummy' has learnt how to pedal, change gear, steer, and what will happen to him when the bike comes to a dead stop from speeding! grin





Thank you, Pixel Perfect, for your assistance on this... deleting the leg motion keyframes did the trick.

In the last month I think that I've actually learnt more about character animation than I have in the last 10 years. smile
05-22-2015 05:47 PM
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Ezequel Offline
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Post: #15
RE: My home-brewed bicycle
Really cool! smile
05-22-2015 09:08 PM
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