Integrating 3D models with photography
Interested in integrating your 3D work with the real world? This might help
# 1 15-10-2005 , 11:41 PM
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Surface intersection

please i will like to know if there is anyway you can avoid sufaces from intersecting. For instance if am to animate a guy jumping on a table and i don't want the legs to pass through the table. How can that be done without have to align the legs on the table.


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# 2 17-10-2005 , 12:49 PM
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Do some research on Active and Passive Hard Bodies. Also, check out how to use IK solvers.

# 3 17-10-2005 , 09:36 PM
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passive and rigid bodies can only be used with dynamics


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# 4 18-10-2005 , 11:49 AM
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Yeah, you're right.... I wasn't thinking.

With that in mind, I'd use an IK solver on the legs. If you rig the model right, you'll be able to grab it by the root joint and move it up and down without causing the feet to move. The feet will stay in place instead of going through the table and the knees will bend. You'll have to animate the model jumping up on the table but once you keyframe the feet on top of it, they will not move while you animate the root joint (the pelvis) or any other part of the model. There are a lot of tutorials on the net that show how to set up an IK joint for the legs and arms.

# 5 20-10-2005 , 07:15 PM
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Thanks for the tips, i will try them out very soon.


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# 6 20-10-2005 , 10:31 PM
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You may want to try dealing with constraints. I have only done a minimal amount of work with constraints, so I'm not sure if they can be used dynamically, but its just an idea.

# 7 21-10-2005 , 12:14 AM
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Is there any kind of constraint in maya that can prevent surfaces from intersecting?


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# 8 21-10-2005 , 05:01 PM
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I'm sorry, but I couldnt tell you, I havent spent enough time with the software to tell you.

# 9 21-10-2005 , 06:09 PM
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as near as I know, there is no constraint that keeps things from intersecting. At least not as a 'don't let meshes intersect' route.
Personally, I think simply keying the charachter on the top of the table is your best, and easiest, bet. Unless you're looking at his shoes, you can easily key his feet in such a way as to keep his feet above the table, by just a teensy bit.
Yes, constraints can be used dynamically, and often are. You can use a constraint to 'squish' parts of the charachter model (don't ask me how to do that, yet), when they get within a certain distance of an object. But even if you got it to 'squish', you'd still have to key the feet and legs to be a certain distance from the table....

# 10 21-10-2005 , 09:24 PM
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But how do i combine dynamics and keyframing?


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# 11 24-10-2005 , 06:17 PM
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*shrug*
that's one of those - 'it depends on what you want to do' questions.

For example; most robot arms have little pneumatic or hydralic cylinders on them. But keying the cylinders would be difficult and time consuming. So what you do instead is set up a couple of aim constraints to keep the two pieces of the cylinders pointed in the right directions. Then all you need to do is animate the arms, and the cylinders follow along, dynamically expanding and contracting as needed. (well, that's the basic setup, anyways).

There's about a million and 1 examples, for a million and 1 ways to do something. If you gave me an example, I could maybe give you an idea, but this machine doesn't have maya at the moment....

Actually, for deforming shoes for table 'contact', your best bet is probably going to be using the soft-selection tool. Although, again, depending on viewing angle and distance, you could probably get away with actually letting your feet intersect the table just slightly.

# 12 31-10-2005 , 11:01 AM
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sorry for reply later. I have been try out some animation and i think keyframing every single thing is better, but very tedious. I guess that is where the hardwork is.

thank for the anwsers.


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