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rzick
12-23-2005, 06:05 AM
Can this be done? -

I am developing an animation of a bug that swoops down and lands on a small chain (you know, the type with little chrome balls that you might find on a light switch). I want the chain to react to the impact of the bug (moving downward and side to side) while the bug hangs on for dear life. Of course the chain is rather flexible, just as you would find with a real ball chain.

I think I can obtain the most realistic motion for the chain using Motion Designer, but that is presenting a problem because it seems like I will need to keyframe the bug's flight path to the chain.

My first thought was to keyframe the bug as it flys and lands on the chain and then engage a pre-calculated simulation to swing the chain. However, it doesn't appear that I can parent the bug to the chain and have it move WITH the chain as it the chain swings (since the swinging of the chain is simulated using MD).

Or is it possible to parent the bug to the chain while it swings even though the chain is using soft body dynamics? Or perhaps the solution is to somehow incorperate the bug into a soft body simulation along with the chain? Keep in mind that the bug will be somewhat of a complex character with beating wings (using expressings), legs, etc.

Any ideas?

Silkrooster
12-23-2005, 04:27 PM
I am thinking hardlink maybe your friend here. ftp://ftp.newtek.com/multimedia/LW8Demos/mov/hardlink002.mov
Silk

rzick
12-23-2005, 04:37 PM
Only thing is I am using LW 7.5. But perhaps this is possible with 7 as well. I'll look at the video.

jeremyhardin
12-23-2005, 05:57 PM
even in 7.5, you could use simpler geometry to simulate higher polygon counts.

so i say...

calculate a two point poly chain in MD with one of the cotton presets and a collision pushing it (where the bug will land).

then 2 chains. one without your bug attatched and one with your bug attached (where it will hit).

use md metaplug and parent the bug-attached one to the 2point polychain. then hide it and reveal it over one frame on impact and hide the flying version of your bug and the first chain. then your bug will be attached to your chain, and the chain and the attached bug will be following the 2 point poly chain.

make sense?

rzick
12-27-2005, 01:02 PM
Yes, that does. I was thinking of basically the same workflow but was unaware of the md metaplug. Is this available from the MD interface?

pooby
12-27-2005, 03:40 PM
You can also use 'make path' to get a null from the dynamic chain and dynamically parent the bug to that.

Celshader
12-27-2005, 03:53 PM
Yes, that does. I was thinking of basically the same workflow but was unaware of the md metaplug. Is this available from the MD interface?

MD_MetaPlug is a playback function for MDD data found in the Deform->Add Displacement section of Object Properties. It is not directly available from the MD Controller. Run your calculations on the low-poly stand-in, save out the results, then play back the MDD data on the high-res object with MD_MetaPlug, with the low-poly stand-in marked as the "Cage" object.

If it helps, I have LW7.5 examples of Motion Designer content for downloading from here, including MD_MetaPlug scenes:
http://www.celshader.com/gallery/md/

jeremyhardin
12-27-2005, 04:05 PM
You can also use 'make path' to get a null from the dynamic chain and dynamically parent the bug to that.
is there a make path command in 7.5 that i missed all that time?

pooby
12-28-2005, 05:07 AM
sorry.. I didn't read the thread properly.

jeremyhardin
12-28-2005, 01:57 PM
ah, fair enough. got my hopes up.