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dsol
03-19-2013, 12:06 PM
I'm currently doing a promo for TV with a mobile phone (it's a lot cooler than it sounds!) and at the end, I want to make the phone bounce around like it's being buffeted by soundwaves. I've built a low-poly proxy for the phone model and animated it using LW11.5's new Bulllet Forces, and it looks great. The problem is, the final model I want to apply the motion to is fairly detailed and made up of a number of sub components that are parented to it (and are also being deformed by an animated greyscale map).

In earlier versions of LW, you could use FX Hardlink or FX Metalink to deform objects using low-poly proxies. But this doesn't seem to work with the new Bullet-based dynamics. Worse, this wouldn't help anyway as I need to keep the sub-objects parented to the body of the phone.

So - does anyone have any ideas? Is it possible to bake out simple position and rotation keys from a single rigid body? Or can you convert a baked MDD file of the simulation for that object and derive position and rotation from 2 points? If so - how?

Any ideas will be massively massively appreciated :)

dsol
03-19-2013, 12:39 PM
I found this (http://forums.newtek.com/showthread.php?134001-Parent-a-null-to-a-Bullet-Dynamic-object&highlight=parent+null+to+bullet) thread, and have tried exporting BDDs using DPont's motion designer tools. No joy so far. Every time I export the motion file, it just comes in with keys all set to zero.

dpont
03-19-2013, 01:15 PM
I found this (http://forums.newtek.com/showthread.php?134001-Parent-a-null-to-a-Bullet-Dynamic-object&highlight=parent+null+to+bullet) thread, and have tried exporting BDDs using DPont's motion designer tools. No joy so far. Every time I export the motion file, it just comes in with keys all set to zero.

This thread is about a object with parts/pieces,
the result is a BDD file,
BDD Scan doesn't read into Bullet cache, but scans the
displacement of the parts,
for one single object,
it needs to be exclusively composed by one part,
if it detects disconnected parts, the Motion File
export couldn't work, but I don't know your
content object and scene so I can't say..

Denis.

dsol
03-19-2013, 01:35 PM
Success! Mentalfish's motion baker script worked. Thank god!
http://mentalfish.com/2009/09/motion-baker/

But seriously, why can't you parent objects to ones driven by dynamics? that would be a very, very useful feature. At the very least, useful for working with low-poly proxy objects!

dsol
03-19-2013, 01:44 PM
This thread is about a object with parts/pieces,
the result is a BDD file,
BDD Scan doesn't read into Bullet cache, but scans the
displacement of the parts,
for one single object,
it needs to be exclusively composed by one part,
if it detects disconnected parts, the Motion File
export couldn't work, but I don't know your
content object and scene so I can't say..

Denis.

Thanks Denis. As you may have gathered, I'm a bit of a newbie about how MDDs and BDDs work. The object I'm trying to read is a single piece object, about 456 polys and a watertight mesh. I haven't defined any parts on it though, so maybe that's the cause.

Anyway, for the moment the Lscript approach worked, so I can crank back on with this project. This is the first time I've really pushed Lightwave on a job for a long time, and I look forward to sharing the final result soon (it'll be on BBC channels from next week!).

Thanks again,

Dan

ps. and once I get paid, I'll punt some cash your way too. Bit overdue really :)

jeric_synergy
03-19-2013, 02:07 PM
I think when Denis says 'parts', he is not referring to the LW Parts feature, but contiguous sets of polys such as one gets when one uses 'Select Connected'.

But perhaps Nodal Motion would allow you to attach ('virtual parent') Objects to specific points on a given mesh, even when under Bullet control. I mean, it should, right?


I too have ZERO knowledge of MDDs and BDDs work. That'd be a good LightWIKI article or L3D tutorial set, especially as there seems (frome reading here) to be a few 'gotchas!' in the process.

pinkmouse
08-28-2013, 05:45 AM
I got thinking about this after a pub conversation with Dan last night, and just tried straight parent/child relationships:


http://www.youtube.com/watch?v=9OiJsnFL3LE&feature=youtu.be

So, it's either fixed in 11.6, or you were trying to get too clever. :D

dsol
08-28-2013, 06:20 AM
Ah - very interesting. Maybe they added support for rotations in 11.6. In 11.5 you could parent it, but only XYZ movement was shared (no rotations).
This will make dynamics a lot easier to set up in future - thanks for testing!