View Full Version : MDD scan, ClothFX scan: what are the limits of applying the result?/Potentials?

09-02-2014, 10:03 AM
I've seen mulitiple posters here reference using ClothFX and (something else??) to scan a deformation subject deforming over time, and then apply the result to different geometry and/or Bones. (Erikals was the latest.)

I'm always surprised that this is possible, due to the differing point count involved. Obviously it's more flexible than I think.

I'd like to know:

A) what is that something else??, if any, and
B) what are the limits of applying the resulting MDD (?) file?

Maybe B) is too negative- what are the POTENTIAL applications for applying the resulting file, whatever it is?

Pointers to good tutorials gratefully appreciated.

09-02-2014, 10:28 AM
You don't apply the scanned data to different geometry. You need to use metalink for that. What you do is you link a highress model which can have a different poly count to the lowress model that needs to have the exact same poly count and point order as the moment the mdd was created.

A. MDBaker and MD multi baker is something else. ClothFX is a bit the old method and the method that works if you want to use an mdd file to drive a different model like a Highress version of the same model.
B. You can bake to geocache and that can be used in maya for example. In maya you can generate geocache that can be used in LW etc.

For someone who reads the manual it's striking that you missed that chapter.

09-02-2014, 11:03 AM
Normally, point order is very important. If you have the same number of points between objects, you can sometimes fudge this by switching to point match mode but that's not what we're talking about here.

Using a lower res cage on a completely different mesh is certainly possible. Back when I was using ClothFX for most of my simulations, I use boxy shapes as cage objcts to animate dense groups of two-point polygons chains for Sasquatch hair guides. This method was much faster to simulate (minutes vs. hours) and much more controllable that applying ClothFX directly to guides.

There are few options for doing this:

- If you use ClothFX, the old stand by is FX Metalink. It's fairly reliable and the results are usually great. Simply parent your high-res object to the scanned low res object and apply this plugin. It's important to use ClothFX to do your scanning though--it will not work with other MDD scanning tools.

- If you're using something other than ClothFX for scanning, you'll need to use one of the other 'meta' tools. The native tool is a displacement node one called Metalink. IMO, it works less reliably than FX MetaLink though and is a bit limited by comparison. But if you can't use the FX version for some reason, you should check it out. (Note: If you have an .mdd that came from another program, you can still use FXMetaLink--just use ClothFX to rescan the object with the third-party MDD applied and save a new 'ClothFX approved' MDD. (And, yes, in case you're wondering, not all MDD files are create alike.)

- Another option is DP MetaFit. This is a variation of the Metalink node tool that, IMO, works more reliably than Metalink node. The catch is that it automatically does a scan when you add the node or load the scene that has an existing Metafit setup. That's fine but if you have a dense object (like hair guides,) it may take a while for your object to load.

The other thing to consider is the shape of the cage object you will be using. I think the way these tools work is that the child object is deformed by an influence from the vertices of the object (kinda like tiny bones.) In general, you may want the spacing of the vertices to be fairly evenly distributed but this really depends on the object you're deforming and how you want it to be deformed. Experiment with different shapes and density to see what works best for your situation.

When I was doing this with low-poly cages for hair guides, I usually just used extruded boxes to animate long hair in locks or groups of locks. It's been a long time since I used ClothFX for hair but I animated the long hair for the female characters in the Saboteur in-game cinematics this way (the pre-rendered stuff that was done at the Box,) using ClothFX and FX Metalink to attach and animate hair on characters that were being animated in Maya.

Hope this helps.


09-02-2014, 11:15 AM
I don't know what you're animating but just to add to may 'hair' example, it helps to break apart the static elemements from the moving ones, and sometimes you may want to break the moving parts from each other. This allows you to use different ClothFX settings for each part, making it more controllable.

Also, I liked to do my sims in a separate scene that included only the objects being used for the simulation. This will save you a lot of time processing (most of my sims took only a few minutes even for lengthy shots,) and keeps the scene reasonably interactive. When you're done, export the mdd(s) and import that to your final lighting and render-ready scene.


09-02-2014, 08:19 PM
For someone who reads the manual it's striking that you missed that chapter.
Ok, here's the thing: last week I specifically Advanced (PDF) Searched for MD_Baker in the dox, and got zero hits. Included trying alternate spellings (the damn underline).

Just now, got 9 hits.

What The Hell?

Also, it sounds like 3dGFXStudios and Greenlaw are contradicting each other: too many points of ambiguity for me to tell right now. Now that I've actually got some hits I'll try to unravel my confusion.

09-03-2014, 07:45 AM
I know it can seem confusing if you've never used any of the 'MetaLink' tools before but it's pretty easy once you've done it a few times. Here's the general workflow:

1. Do your animation or simulation to the lo-res cage object.
2. Scan the animation to MDD. There are many tools for scanning to MDD, but if you want to use FX MetaLink, you MUST use ClothFX.
3. Apply the MDD to the mesh. If you're using dynamics, you should disable it now. At this point I usually work in a clean scene with just the mesh--this prevents conflicts or any unnecessary processing by dynamics or whatever else you may have used for animation.
4. Parent the hi-res object to the lo-res cage.
5. Apply FX MetaLink to the hi-res object. Watch the magic!

Naturally, if you're using sub-D objects, you'll want to use the appropriate settings.

When you're ready for more advanced usage, check out FX MetaLink Morph--this allows you to add morph displacements on top of FX Metalink.

And just to make matters more 'confusing', there is also FX HardLink to consider, which works in a similar way but used for different results...but let's go into that after we sort out the basics. :)

Hope this is helpful.


09-03-2014, 07:48 AM
Give me a minute...I'll post a simple demo scene for you to walk through.


09-03-2014, 08:28 AM
Okay, here you go:


The package has two scenes, one clean scene to work with and one completed scene to reference. Here's the walkthrough:

1. Open the clean scene. In this scene you'll find a 'hiRes' cylinder object and a 'loRes' rectangular cage object. As you can see, the objects are not similar to each other in any way other than general size and shape.

2. If you scrub or play the timeline, you'll notice that the cage has bones animation on it. Currently, the cylinder is unparented and has no animation on it.

3. Now let's get started. Select the cage object and open the Object Properties panel. Apply ClothFX in the FX tab.

4. In ClothFX, select the File Tab. At the very bottom, click on Scan Motion. When scanning is done, give the MDD a unique name like 'myTest.mdd' and save it.

5. Normally, you would apply the MDD to your object. There are many tools available to apply this MDD, but in this situation it's been automatically applied by ClothFX. In other words, ClothFX is currently the MDD Player for the animation and you don't need to apply the MDD--it's already been done for you. To check this, you can disable Bones and the animation on the cage should still be active through the MDD displacement.

6. Now comes the fun part: FX MetaLink. Select the 'hiRes' Cylinder and parent it to the 'loRes' cage with the MDD. You can do this in the Scene Editor or Motion Properties panel.

7. Open the Object Properties panel for the Cylinder and select the Deform tab. At the bottom of the panel, add FX MetaLink.

8. Scrub or play the animation. The cylinder should move with the cage.

I used bones animation here but this works for almost any type of mesh animation including ClothFX, Morphing, Bullet, etc.

Things to remember:

- For FX MetaLink to work, you must use ClothFX to scan the MDD.

- There are other 'link' tools available, like nodal MetaLink and DP MetaFit. These nodal variations do not require ClothFX, which is a benefit in certain cases. However these tools have limitations which may make FX MetaLink preferable in other situations. Experiment to find out which method works best for your specific situation.

- If you have an existing non-ClothFX MDD created elsewhere and need to use FX MetaLink, you can scan a new ClothFX-blessed MDD from the object with the non-ClothFX MDD applied. To do this, apply the MDD using MD Reader and then apply ClothFX. Scan as described above. When the ClothFX scan is completed and saved, remove the MD Reader with the original non-ClothFX MDD to prevent conflict with the ClothFX MDD. Also, remember that ClothFX automatically applies its own MDD file after scanning.

Well, that's the basics. As you can see, these tools are really not that difficult to use but they are certainly powerful. I've used this method and variantions of it to animate a gazillion hair guides, deform hi-res clothing, add jiggle or morphs to MDDs after baking, attach accessories in Lightwave to pre-baked animations from Maya, and all sorts of cool tricks.

Hope this helps get you started. :)


09-03-2014, 08:34 AM
Greenlaw, THANKS very much for your help, you are extremely generous. I look forward to internalizing all the above.

09-03-2014, 08:44 AM
One thing I forgot to mention: I you double-click on FX MetaLink, the option to use Smoothing appears, which affects the influence of the cage object. Depending on the object you're deforming with FX MetaLink, you may want to disable or enable this feature. Try it in the above walk through and you'll see the difference.

Thomas Leitner
09-03-2014, 11:47 AM
- If you have an existing non-ClothFX MDD created elsewhere and need to use FX MetaLink, you can scan a new ClothFX-blessed MDD from the object with the non-ClothFX MDD applied. To do this, apply the MDD using MD Reader and then apply ClothFX. Scan as described above. When the ClothFX scan is completed and saved, remove the MD Reader with the original non-ClothFX MDD to prevent conflict with the ClothFX MDD. Also, remember that ClothFX automatically applies its own MDD file after scanning....

Two little notes to this workflow:
1. You don't have to scan your MDDs through ClothFX, you can load the MDD directly into ClothFX (File tab > Load Motion).
2. There is also a displacement modifier called Metaplug that allows using MDDs from a cage object directly. You load the MDD file and specify the cage object. However the displacement is not exactly the same as with metalink (by the way: using Metalink NODE in the Displacement Node Editor seems to deform like Metalink Modifier).