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ollak
02-16-2009, 04:13 AM
Hi

I have two questions. To explain the first one, you'll need to visualize something. Imagine I have a cylinder with a length at 5" and with an inner radius at 2 ". The cylinder has no top or bottom. Inside this cylinder, I have a rod, or pipe if you like, with the length of 7" and an outer radius at 1.5". (Since the 7" rod is longer than the 5" cylinder, 1" sticks out at each end of the cylinder)
Is there anyway I can align the polygons from the inner wall of the 5" cylinder, to the outer walls of the 7" pipe? In other words, no matter how much I rotate or move the 5", I want the 7" to "follow" and the distance between them to remain the same all the time. With one exception; I want to be able to slide the 7" along the inside of the 5" so fixating it in anyway will defeat it's purpose.

And the second question; Im modelling a robot, with visible joints and moving parts. Is there someway I can rig it using something else than bones? Since I dont want the squisch effect you get when animating a human arm or any flesh-like material, I suppose bones are not the best way to rig.

Appreciate any help!

//B from Sweden

Sensei
02-16-2009, 05:21 AM
If cylinder geometry and pipe geometry are one layer, they will rotate and move together. But if they're different layers or objects, you can make them follow other item by making one parent of other. In Motion Options (press 'm').




And the second question; Im modelling a robot, with visible joints and moving parts. Is there someway I can rig it using something else than bones? Since I dont want the squisch effect you get when animating a human arm or any flesh-like material, I suppose bones are not the best way to rig.

Use Weight Maps Only bones (so one bone will drive just one robot part), or place every part in different layers, parent them, and keyframe every part as you wish.

flakester
02-16-2009, 07:25 AM
~ or place every part in different layers, parent them, and keyframe every part as you wish.

Agreed. Foward Kinematic [downstream] systems are best for robot-arms and mechanical devices. For a robot biped or where you need to lock and/or move feet, Inverse Kinematic [upstream] systems work best for the legs, for these; do as Sensei suggested and opt for weight map only bones.

--
flakester.

SplineGod
02-16-2009, 07:34 AM
You can also use bones but parent the robot parts to each bone.
Different parts of the robot can be rigged up separately in its own scene then imported and parented to a particular bone. This can make it alot easier to build separate systems, verify that they work then apply them to particular parts of the robot.

flakester
02-16-2009, 07:53 AM
You can also use bones but parent the robot parts to each bone.
Different parts of the robot can be rigged up separately in its own scene then imported and parented to a particular bone. This can make it alot easier to build separate systems, verify that they work then apply them to particular parts of the robot.

Ace suggestion. Think I tried something akin to this quite a while ago to see if it would help in a piece we were doing. Turned out to be quicker for us to go a pure FK route for that particular project [and its tight turnaround], but assigning parts to their own bones does make for a very versatile system.

Good call, SplineGod. :thumbsup:

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flakester.

SplineGod
02-16-2009, 08:40 AM
Thanks!
Another reason to use bones in this way is for selection purposes.
With the potential for so many objects selecting can become a real pain. Having to select only bones can make it much easier.
You can also hide or softlock objects so you can only select bones in teh viewport.