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Oldcode
04-10-2016, 10:15 AM
Hi Everybody,

I've got a situation where I have a character walking through a jungle, moving vines out of the way as they do.

To help figure out how to do this, I've been looking at Top of 33 Multimedia's You Tube tutorial that seemed to be just what was needed.

https://www.youtube.com/watch?v=IW9CLDMK0bU&list=PLRuAjY2w04PktRp1cDh1pVcD9DeTiJzK7&index=21

Using proxy objects, having my character push the vine out of the way as they walk seems very straight forward. I have LW 11.6.3 and when I follow all the steps in the tutorial, everything seems to work until I get to part where I apply FX_Metalink to the vine object. Check out the pictures below.

Before FX_MetaLink
133373

After FX_MetaLink
133374

See how the vine object is distorted? When I scrub through the baked animation, it gets even worse. There are two ways to apply FX_Metalink to the object, and I've tried both. The results are the same.

At first, I thought it was some problem with the geometry of the vine. But as an experiment, I tried a very simple cylinder objects with enough segments to allow it to deform, and it does the same thing.

Anybody seen this before?

Thanks in advance,

MonroePoteet
04-10-2016, 11:49 AM
I'd guess you don't have the Weight map set up correctly, or didn't specify it as the Mesh Filter on the guide. I did a quick Bullet setup (I've done that same chain video before) similar to what you describe, and although the vine really flops around because I haven't tuned the damping, it works as I'd expect.

Note that you have to press the Calculate button on the FX tab of the guide (which has Soft FX added) to have the FX subsystem calculate the Metalink to the modeled vine. Another note: Bullet or the FX subsystem seems to quit calculating on the last keyframe of the Collision object, so I rotated it to 90 degrees at frame 120 to complete the simulation.

mTp

Oldcode
04-10-2016, 04:19 PM
Hi Monroe,

Thanks for your response. I was able to get it to work on your scene file, but not on mine. They never mentioned using Soft FX in the tutorial, so I'm confused is to how you use that. I've attached the model of the vine I'm using. If you don't mind, can you take a quick look to see if there's anything wrong with the model itself, and then send me the scene file so I can figure out how you did it?

Thanks! :D

MonroePoteet
04-10-2016, 05:22 PM
No, there's nothing wrong with the model file. It works the same way as mine.

Here's how to use it with the Vine_Collision object I sent in the previous ZIP file:

1) Load the Vine
2) Select Layer1 (BTW, I usually rename the layers in Modeler using F7, double click on each layer)
3) Set it to a Deforming Body using FXTools=>Deforming Body
4) Use FXTools=>Item Information to set the Mesh Filter to weightmap Weight 1
5) Use the Properties=>FX Tab Add FX to add Soft (FX) to tie it to FX_Metalink
5) Select Layer 2
6) Using the Motion Panel (m), set Layer 2's parent to Layer 1. This must be done for FX_MetaLink
6a) You can set up the parenting hierarchy in Modeler as well using the F7 & double-click
7) Using the Properties Panel Deformations tab, add FX_MetaLink
8) Select Layer 3, do steps (6) and (7) for it as well
9) Load the Vine_Collision object
10) Move it down the negative Z axis for Frame 0, move to +Z at Frame 30 (to collide with the Vine)
10a) Also keyframe something at the last frame to keep Bullet calculating the effect
11) Go to Frame 0 to start the simulation
12) Use the FX_Tools=>Kinematic Object to add the Vine_Collision object to Bullet
13) Play the scene, and you'll see the guide (Layer 1) waving around.
13a) As I said previously, the weight / damping needs to be tuned up to make it a little less lively
14) Back at Frame 0, use the Vine_Collision Properties=>FX Tab and press the Calculate button
14a) What you *should* see is the Vine geometry now tracks the Layer 1 guide

I've attached a scene with this setup using your Vine and my Collision object, but hopefully you can reproduce it. I also added a damping envelope to keep the guide / vine from flopping around too much. It's very IMPORTANT that each time you adjust the Bullet simulation (or first load the scene), that you use the Layer1 (Guide layer) Properties=>FX Tab=>Calculate to recalculate the Soft FX influence on the MetaLinked geometries.

To adjust the Bullet simulation, I disable the Soft FX while adjusting Bullet parameters, and always (ALWAYS) go back to Frame zero before trying to make any Bullet changes. Yes, I know I can Disable Dynamics and re-Enable, but "f" then "0" is really quick and almost automatic for me anymore. While adjusting the Bullet simulation, I ignore what (if anything) the Metalinked geometry is doing (probably the old Calculated SoftFX) and just watch the Guide. When the Guide is doing what I want, then enable SoftFX again and press the Calculate button to tie in MetaLink on the vine geometry layers,

Hope this helps, and good luck!

mTp

Greenlaw
04-10-2016, 07:37 PM
They never mentioned using Soft FX in the tutorial, so I'm confused is to how you use that. I've attached the model of the vine I'm using. If you don't mind, can you take a quick look to see if there's anything wrong with the model itself, and then send me the scene file so I can figure out how you did it?

Thanks! :D

I don't know if this has anything to do with the issue you're running into as I haven't seen the tutorial and I'm just skimming this thread (sorry...in a hurry right now), but for FX_Metalink to work properly, you need to use one of the old dynamics tools to scan the mdd. FX_MetaLink won't work with other MDD scanners, including the 'native' LW3DG tools. This is because the FX tools were developed by a third party about 15 years ago. When I want to use FX_Metalink, I usually use ClothFX to do the scan but SoftFX, as suggested by MoroePoteet, would work too since it comes from the same suite of 'FX' tools.

More recently, I've been using DP Meta Fit for 'metalink' effects. This tool work work a little differently in that it does its own point scanning immediately when you add the tool. I usually bake the animation to a regular MDD when I'm satisfied with the result to prevent the tool from re-scanning every time I open the scene. (After scanning, you'll want to remove DP Meta Fit of course.)

There is also the native MetaLink node, which doesn't require scanning either, but it has a limitation. I can't think of what that was off the top of my head but I think it had to do with not being able to use the Metalinked object collision. DP Meta Fit doesn't have this issue.

It's been at almost two years since I used any of the above tools but I think this info is accurate.

If none of this has to do with the issue, never mind. :)

G.

Oldcode
04-11-2016, 06:48 AM
Thanks guys!

I was able to get it to work. Greenlaw, I tried using the both MD_Baker and ClothFX to create the MDD, but when I did and tried to apply it to the polygon chain, it keep giving me an error, which may have been why it was distorting the geometry.

Anyway, by totally leaving out ClothFX and using SoftFX, I was not only able to get it to work with a low polygon proxy mesh, but with my character model as well, which will save a lot of setup time. The key was to increase the collision distance on both the polygon chair and the character mesh to make it look right.

The shot will call for dozens of vines which will be a lot of work to setup, but if the dynamics work, it will be far less work that manually animating the vines to react to the character's arm movements. I've done a shot like that with 4 vines, and it worked, but it took a hwile.

I'll try to post some pictures or a clip tonight.

Thanks again! :D

Greenlaw
04-11-2016, 09:03 AM
Good to hear you got it working.

It's odd that scanning with ClothFX didn't work but, yeah, MDD files created with MD_Baker will not work for FX_MetaLink.

MonroePoteet
04-11-2016, 09:29 AM
Also in Bullet simulations you can get better collision detection by increasing the Item Properties=>World tab=>Dynamics Framerate above the default of 180. Setting it up to something like 600 gives better collision detection, although it's slightly slower. I think this makes the Bullet simulation calculate mesh movements between Layout frames at a higher granularity for collisions. With a lower Dynamics Framerate, it's easy for the colliding meshes to "go too far" past where the collision would have been detected.

mTp

Oldcode
04-11-2016, 10:07 AM
It's odd that scanning with ClothFX didn't work but, yeah, MDD files created with MD_Baker will not work for FX_MetaLink.

Agreed, because that's what Top of 33 Multimedia's You Tube tutorial used and it seem to work for him.

Thanks for the tip on the Dynamics Framerate Monroe. I'll check that out tonight. My character models are from poser imported via PoserFusion, so they are really polygon heavy, some would say unnecessarily so. So anything that will increase the performance of the collisions will be welcome.

Cheers! :)