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egearbox
01-05-2014, 10:28 PM
I think there's a technique for this, I just can't remember it: Deform a low poly object with FX, save the MDD file, then use the low poly MDD file object to deform another higher-poly-count copy. Am I dreaming?

jeric_synergy
01-06-2014, 01:16 AM
FX_MetaLink? Something like that....

bazsa73
01-06-2014, 03:44 AM
You have to parent to hires mesh to the lores and apply FX_Metalink on the highres. Set subdiv order to last but you dont need the MDD while testing. If you run the sim
on the low res you get instant feedback when you replay the stuff.

daforum
01-06-2014, 05:38 AM
Have a look at this tutorial: http://m.youtube.com/watch?v=8_-8a5q7HFE&list=PL44352D66C707E2B9&feature=plpp

Hope it helps :)

prometheus
01-06-2014, 12:07 PM
also this one from William Vaughan...
metalink and morph...
http://www.youtube.com/watch?v=Z9_9XV4oMrI

I think thereīs one more showcasing a cloth object at lo-res and then linked to a higher res mesh...but canīt find it.

Michael

Dodgy
01-06-2014, 09:35 PM
My video goes over the workflow:
http://www.youtube.com/watch?v=uBJ50fCRdlU&feature=c4-overview&list=UUV1ks2APY9Mn21UlSJe4IcQ

egearbox
01-07-2014, 08:54 PM
I'm guessing that I used the term "FX" too loosely - I was looking for something that would work with Bullet Dynamics. Carefully reading the manual and watching the tutorials, plus over an hour of frustrating experimentation, seems to indicate that the FX_Metalink and FX_Hardlink only work with Cloth or Soft FX. Is that in fact the case? :(

prometheus
01-07-2014, 09:06 PM
I'm guessing that I used the term "FX" too loosely - I was looking for something that would work with Bullet Dynamics. Carefully reading the manual and watching the tutorials, plus over an hour of frustrating experimentation, seems to indicate that the FX_Metalink and FX_Hardlink only work with Cloth or Soft FX. Is that in fact the case? :(

Mjaaa..I think some things work, here was a simple test I did, canīt recall for sure, but I think did a bullet sim on a polystring then metalinked first a cloth object then a bullet softbody, but I am not sure, there
was a thread somewhere about that where the process was discussed.

http://www.youtube.com/watch?v=yAP5sbBC3qU


There are problably some limitations since I think it was developed more specific for clothfx, guess you have to try some different metalinks and bullet softbodies.

Michael

jeric_synergy
01-07-2014, 09:07 PM
Most (fwiw) Likely is that any MDD mediated distortion will work with FX_Metalink.

So, if you can MDD scan your simulation, it's probably applicable. Please note the weasel words herein.... ;)

egearbox
01-08-2014, 12:11 PM
Most (fwiw) Likely is that any MDD mediated distortion will work with FX_Metalink.

So, if you can MDD scan your simulation, it's probably applicable. Please note the weasel words herein.... ;)

Weasel words noted. <grin>

I initially tried an MDD file saved/loaded from Bullet, against a low-poly mesh (not a 2 point string). I could see the low poly object deform, but not the high poly object. Maybe it only works with 2 point polys, I don't know. I tried several different variations with absolutely no luck. I guess I'll just punt and go back to deforming the high-density mesh directly - that'll probably give me better results anyway.... :)

jeric_synergy
01-08-2014, 01:52 PM
As long as you are solid with the workflow to making FX_metalink work at all (several steps, easy to screw up), I concede your diagnosis.

egearbox
01-08-2014, 09:48 PM
119163

Yeah, I tried again with Bullet and Metalink, and no go. Here's the scene if anybody wants to try it. It'll be cool if someone can make it work.

Dodgy
01-08-2014, 11:57 PM
Seems to indicate that the FX_Metalink and FX_Hardlink only work with Cloth or Soft FX. Is that in fact the case? :(

That is in fact the case. It's really very simple. Apply clothFX to the low poly object (even if you're animating with bullet) and in the File tab, click Scan and save the .mdd file. Then have the High poly object as the child of the Low poly object and apply Metalink to it (this is the part you already have done). Metalink (or hardlink if you need that instead) will then deform the high poly object.

You don't have to have clothFX actually calculate, you just use it to play the .mdd file and it will work.

jeric_synergy
01-09-2014, 01:29 AM
That whole thing of using ClothFX to record other subsystem's deformations is VERY confusing and non-intuitive.

If they made a cut-down version called RECORD_DEFS , it would be better.

egearbox
01-12-2014, 03:45 PM
That whole thing of using ClothFX to record other subsystem's deformations is VERY confusing and non-intuitive.

If they made a cut-down version called RECORD_DEFS , it would be better.

I just ran a test and you can create the low-poly MDD with bullet, save it with MD_Baker and just load it back into the low-poly object with Cloth_FX. You only have to use Cloth_FX to play it back and FX_Metalink will pick it up. Still awkward but at least it works! :) (happy happy!)

Ivan_B
02-18-2014, 02:49 AM
Hi All,

I recently had to animate a phone cord and this thread popped into my mind...

This method of baking the 2 point poly chain and using clothFX to drive the animation allowing for metalink to work is perfect, so I made a video tutorial, this is a handy trick to know and it might help others.

Thanks for sharing the info...thought I'd pass it on.

Lightwave Bullet Dynamics & FX_Metalink video (http://www.youtube.com/watch?v=IW9CLDMK0bU).

Ivan.

jeric_synergy
02-18-2014, 01:08 PM
Nice tutorial: clear and brisk, well done!

Ivan_B
02-18-2014, 07:40 PM
Thanks Jeric,
I got a post on the youtube video from Mr Lino (thankyou sir), and he tells me it can be done with a metalink node directly used with bullet no need to mdd, gonna investigate and see if I can get it to work, if so Ill make a quick tute.

EDIT: LOL!!! just had a look and it is sooooo simple, i will make a video, but this is how it works.

1: Deform your 2 point poly chain with bullet.
2: Select your high poly object, go to object properties for it .
3: Select the deform tab.
4: Edit nodes for displacement.
5: Select the metalink node, plug it into the "displacement input"
6: Click on the metalink node and choose the 2 point poly chain.

DONE!!! works like a charm!! Thanks lino!

Lightwave has many secrets that need to be revealed...get to it people! lol!!

jeric_synergy
02-18-2014, 08:09 PM
Dammmmmmmmn, there's a Metalink displacement NODE? Sheesh. :chicken: 8~

Software really shouldn't have 'secrets'!!!!! :cry:

Thanks for the hedzup!!! :thumbsup:

Ivan_B
02-18-2014, 08:18 PM
LOL Here's the new Bullet Dynamics & Metalink NODE video (http://www.youtube.com/watch?v=DRBY0vQmsJc).

How stupid do you think I feel, making videos of old technology lol!

djwaterman
02-18-2014, 08:58 PM
Super helpful.

jeric_synergy
02-18-2014, 09:28 PM
I decided to follow your lead and test this out: when I followed what you did with no additions, everything worked as depicted. ("Yippee!")

Then I decided to add a ground plane to interact with the 'string'. Firstly, this massively slows down the simulation, but I expected as much, and blame my probable incompetence w/Bullet as much as anything (iow, no doubt I'm using sub-optimum values and settings).

Second, however, is a true bug: After adding a (Layout) ground plane and making it a dynamic object, I noted that the chain was no longer deforming. Checking the node, it was now pointing at the ground plane, the 3rd object in the Scene, rather than the 'string', the 2nd object in the Scene.

Correcting the node object setting caused the chain to collapse in on itself at the Origin. :confused:

This type of situation is why I've been avoiding Bullet: the second I step beyond the borders of an example, everything goes pear-shaped in a very frustrating way, compounded by the (not unreasonbable) slowness of the simulation (inherent in the exercise).

So, that's a bummer. :bangwall:

ps: trying to Package Scene this for submission locked up Layout......

pps: 2nd try locked up Layout on simulation, so wasn't even able to get to Export stage.... posting anyhow....

120260

ppps: added test object: RW dimensions quite large, but I'd think the mesh itself is valid.

Ivan_B
02-18-2014, 10:38 PM
Your welcom DJ

Hey Jeric...Bit confused with all that, however I went and tried adding a collision object and used the metalink node and it worked fine.

It calculated instantly. You cant use a ground plane (single poly), it needs to be an object with thickness, use a cube and stretch it out, only needs to be eg 10mm thick.

Here some grabs of it working.

120261

Ivan_B
02-18-2014, 10:47 PM
Hey Jeric...I just downloaded your file and tried it...first up your objects are huge (maybe you need it that big)...Your right as soon as I metalinked the chain layout froze!!!!

I found the problem to be the object itself..weird stuff...anyhow I deleted all but the 2 point poly chain and your high poly chain and resized it down to 10m, added a collision cube, tried it and it works fine now. It really really helps to work in real world sizes, I guess all the math associated relies on that. Your chain is 10m long now and the simulation shows that..the chain is slower and looks heavier.

120264

Try my scene if it helps.


120263

Dodgy
02-18-2014, 10:56 PM
I find the node can be fussy when it comes to subdivision objects, hence I tend to avoid it. The metalink+ClothFX combo always works, and you don't have a hardlink node either, much as I begged for it and the metalink node to be fixed.

Ivan_B
02-18-2014, 11:19 PM
Hey Dodgy...I'm glad that I did make the video using the mdd and cloth method now...Just in case the node packs up.

Next tutorials gonna be on wood fracturing and bullet, so as to get wood splinters that look realistic.

jeric_synergy
02-18-2014, 11:37 PM
Hey Ivan_B, thanks for taking a look at that: I wasn't really paying attention to scale, hence the unreasonable size.

That type of error (things pointing to the wrong Object when new objects are loaded/created) used to be a fairly common bug, so I wasn't really all that surprised to see it. I think there's an upgrade note in the latest about switching to objectID or something, so maybe that last update will address this.

I'll give the solid collision plane a whirl tomorrow, thanks for the info about just straight polys.

And Dodgy: yes, a companion "HardFX_Link" node would certainly round out the offerings.

jeric_synergy
02-20-2014, 10:59 PM
OK, so I reduced the object to a more reasonable scale, each link is 50mm long, and the Bullet object is scaled appropriate to that.

As before, the 'string' simulated just fine.... oh wait, forgot to DE-subd the chain, BRB.... OK, (whew), with subd off it works fine. With subd ON, it pretty much locks up the machine with subpatch level=3. Also, with subd'd mesh, a SUBD DISPLAY LEVEL=0, all works fine.

OK, now here's a puzzle: PREVIEW subd of 3 locks up the machine, but RENDER subd of 5, no apparent effect. WUWT? It would appear subdivision has an ENORMOUS overhead when Bullet is in use, for the UI display.

Attaching the SUBD'd version of the scene+mesh.... (you can kill layer#1+#10, they're not doing anything.)
120290

++++
DODGY, what needed to be fixed ( your post above) ??

Ivan_B
02-21-2014, 01:39 AM
Hey Jeric,

I had a look at your scene, Your right it locked up LW when subd, as soon as you choose to link it to the 2ptpoly...turned subd off and I imported the objected and set it up, couldn't get it to link via the metalink "node", but it did work with the mdd and cloth..confused.

EDIT: It does work with the mdd & cloth when the chain is NOT subd, BUT if you subd the chain whilst layout is open with the setup and switch to layout, lightwave freaks out so bad it turns the software to discovery mode and locks up LOL!!!!!

The simplest fix would be to make the high poly chain with a lot less polys, less detail in the links...its flapping around with motion blur, wont see the detail anyway.

jeric_synergy
02-21-2014, 10:04 AM
Hey Ivan, thanks for taking a look at that: now I know I'm not mad.

Since this is just mucking about no fix is needed (no cash at risk), but it certainly illuminates some weakness in LW that should probably be examined by the devs. I'm suspecting some (unneeded) computation loop is being invoked, and if they could untangle that it would very likely help subd performance in general. (Or make it worse: nobody knows.)

It just seems likely given that it will RENDER much more quickly than it will display in the UI-- that's not good. :screwy: 8~

jeric_synergy
02-22-2014, 12:49 AM
So latest update: although it was working fine w/zero collision objects, once I added a box to collide with, the 'string' uhhh, 'came loose' from it's mooring and it and the chain slipped down and over the box!!!!

WUWT???
+++++
So, recreated the scene from scratch, got weird stretching and collision object penetration. Again, Bullet just seems too flakey to use.

I even extended the "fixed" portion of the weight map so it wouldn't FALL: now it stretches. :sigh:

120300

jeric_synergy
02-22-2014, 02:12 PM
#coffeeshopmode
Additionally, I again ran into the bug that, when I added another Object to the Scene, the Metalink deformation node became pointed at the wrong reference object. :sigh: