Help me animate a v-8 curtiss ox-5 please!

Bongo
1

I’ve been using rhino since v1 but i cant seem to figure out bongo. i’m building a curtiss ox-5 engine and i have most of it done, id like to animate it. i would be grateful to anyone who could animate this model and explain how they did it.
jenny engine.3dm (18.4 MB)

2

Hi Jon,

I animated 1 piston in your model. The rest is up to you.
jenny engine 001.3dm (19.0 MB)

The “crankshaft” is keyframed to rotate 360°.
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The pivot of its child “rod” is moved to the position of its junction with the crankshaft. It is made a IK-joint, Hinge, X‑axis.

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“spindle” a child of “rod” kind of ends the basic IK-chain. “spindle” is allowed to rotate with respect to “rod” – hence it’s a joint, hinge, X-axis – and it is also constrained to “track” (the center line of the absent cylinder) to make it move in the correct direction.

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“piston” a child of “spindle” also is constrained to “track” to keep it in the same correct direction.

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Both constraints are necessary because Bongo’s constraints operate on the origin of object’s pivot which is a point. In order to define a line one needs 2 points (at least).

Allow me to recommend a viewing of my video Whys of IK in Bongo 2.0 - YouTube

Luc

BTW there is a sample model of a piston engine on Rhino - Sample Models

3

thank u luc

4

i guess im a compllete idoit, ive spent hours trying to get the next pisston to work. do i need to create an entire new ik chain? and it wont let me constrain to a track, idny

5

Jon,
Do not despare. Take a look at the Animation Manager in the sample model mentioned above (at Rhino - Sample Models)
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There are 4 IK branches that share the same ‘driving head’, namely the object “cranshaft”. Each branch ends in its own constraint.
For your V8 engine you obviously need 8 branches.

As for establishing the constraint, I guess you’re puzzled because the option “Constraint to object” appears grayed-out.
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You simply have to click the ‘Select target object’ button to get going. I agree it’s a bit confusing.

Have an other try. When the hours or the patience to spent run out I can do it for you. Just give me a sign.

Luc