Cineversity

Hello

I have some animated characters that I would like to use to deform cloth objects.  The characters are dancing, and they collide with cloth panels.
I’ve noticed that because, for example the fingers or the toes, are very thin, the cloth will sometimes “explode”.  So I’m wondering if there is a way to use a more “bulky” mesh to deform the cloth, but that would follow the characters movement.
Is that possible?

Thanks!

Hi Alex,

You can always use a “proxy” instead. Which would be invisible, and the original stays visible.
One way to get a perfect Proxy is shown here:
https://www.cineversity.com/vidplaytut/polygon_pen_part_07
Also a primer for cloth after 19:19 [min:sec]
https://www.cineversity.com/vidplaytut/animating_flabiana

Other ways are based on a cached Cloth set up, while the Cloth> Cloth Cache Tool is used to fix problems.
https://help.maxon.net/us/#CACHETOOL

Besides that, in some cases, the cloth have made use of the joint rig, while additional joints are applied.
Example discussion
https://www.cineversity.com/vidplaylist/character_rigging_techniques_siggraph_2015_rewind/

Since I think that a dancer and cloth in one of your set up will have a lot of motion, I do not suggest the typical cloth ideas, e.g., merge the cloth with the body.

Anyway, last but not least:
https://help.maxon.net/us/#11367

I hope that gives you something to work with.

My best wishes for the project

Thanks for this Gold Mine of information Sassi!

I think the joints as geometry option is quite good, but I’m very intrigued by the retopo idea.  What I wonder is if the the new topology will follow the deformed body?  I have to watch the tutorial fully, but I can see it is being done on a static piece of geometry, so I’m not sure how the movement transfers to the new geo?

Thanks!

Hi Alex,

I hope you have a T-Pose for each character, so you can weight the new mesh. Weighting is nothing else than telling points of a mesh how much they have to follow a joint or a group of joints. While re-topologize, think of the joints and how they affect the shape, after all edges are not bend ever, points are moved, and that is all how polygons are working. So, some areas need some smaller polygons than others.

Since I haven’t seen your project, you could also just place a slightly larger [flat] sphere (or something like that) where the hands and critical contact points are. These dummy geometries can then have a Constrain Tag to the Joints in question for that area.

Once I turned all joints to splines and then into a Sweep object, made editable, which worked really fast, and if done in groups the Sweep has a lot of options to get closer to the original shape.

Another idea would be, and I know it is far fetched – but I know how expressive your work can be – so, to place little Wind objects on the hands or other parts. Eventually use fallow to be more defined, and have that Air-pillow effect as well working for you.

I’m happy to explore more, Cloth is certainly a tricky one, when it comes to very fast movements and wide cloth. I certainly have not a library of answer here. I have to explore it individually.

https://help.maxon.net/us/#CLOTHTAG-CLOTH_GROUP_EXPERT

https://www.cineversity.com/vidplaytut/cloth_simulation_part_03

All the best

Thanks Sassi, I haven’t really setup a scene yet, but I will.  I like your idea of the wind in the hands etc, that could be really beautiful!  I’m going to try a few things and upload a file.

Thanks again for your help!

BTW, how did you transform the joints to splines?  I see the option to make “lines”, but they don’t seem to be real splines?

And here is a follow up with a test…The effect I’m trying to achieve is something like this
https://www.dropbox.com/s/kspoii6moi5njvg/PATTERNITY_GOLDFORM_katherineferguson.jpg?dl=0

My first issue is that, even without any character movement, I have a hard time getting the cloth to land nicely on this type of geometry…Even with 100% stiffness and almost no flexion (+ reduced gravity), the cloth still seems to stretch a lot and get destroyed around the hands (See the test I did with a sphere on the left hand).

here is the file
https://www.dropbox.com/s/18v7nxeanavppwr/AfricanDancer_Cloth_2.c4d?dl=0

Hi Alex,

Sorry for the delay, the post #6 created long calculations, hence the delay.

Post #4
You’re welcome, and yes wind and dancers can create a nice synergy. In Wim Wenders’ Pina the outside dance scenes have of course wind (slightly) in it, and it was certainly a plus.

Post #5
Sorry about that. You select the Joints, then Main Menu> Character> Conversion> Joints to Spline.

Post #6

The following makes the fabric nicer, but the side effect that I found with you model, it weakens the collision with the hands, it balloons it.
https://www.cineversity.com/vidplaytut/better_cloth_deformations

Use this selection option
https://www.cineversity.com/vidplaytut/cv-parametric_selection_tag_download_and_install
Noise or Random should work just fine

The Move Sequence Down is useable from the Customize Commands, and there with the execute button. You can see the change while the object is selected in the Structure Manger>Polygons

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The Cloth Object should be used, it adds a lot to the look of the fabric. Polygons by it self can’t do that.

The attached project is not production ready, but I hope it gives some pointers, of how to proceed. The caching here, took with this mesh already very long, perhaps you have faster equipment. Some adjustments need to be done, e.g., Cloth Tag> Expert> EPS, as well as the Iteration, but perhaps more in the Subsampling.

https://www.amazon.com/clouddrive/share/fZx3MrqheTZ5DJJtuQPrDrqE2k7GbTDjmZpE651aync

You can see here where the character pushes through the fabric, but would be perhaps otherwise not be visible. Here another sphere could solve it, or have a shader for that area (via polygon selection) to make it invisible.

Following a few thoughts, that I haven’t seen anywhere else, so test these, as each set up might behave differently:

The way I understand the the Iteration/Stiffness/Flexion mix is, that with each added iteration the stiffness/flexion effect becomes greater. With higher Iterations, the two other values should be lower, to get the same fabric feel, but more precise.

Another impression, to gain the initial fall and faults of the fabric, any values leading to a good result should be used, then set an initial state. If that state is done, set up any values that are favorable for the following parts. In that way things might be easier to art direct.

I explore the idea currently to employ first a rough fabric, which might be then Point Cached (not cloth!) and is used then as a Collider. Perhaps first Cloth Cached, to fix some problems.
The figure would be then eventually not needed anymore as collider. This is currently brainstorming.

All the best

Hi Sassi

Thanks so much for the file, really great to see.  It is a pretty hefty file.  I did find a sort of workaround that is quite nice.  Not exactly what I wanted but I think I can maybe make it work for this project.  See here
https://www.dropbox.com/s/knlpljcepq1e7fe/DancerUnderCloth_1.c4d?dl=0

Hi Alex,

THIS IS GREAT! Sorry about the delay, but I had first to recreate the”.abc” file of the “body” (nearly 300MB!) to get the set-up idea of the scene. YES! This is the missing link. I tried the support cloth mentioned above with cloth, this is the key to make it work. Have to dive into it tonight.

I have set up a small test/exploration file:
https://www.amazon.com/clouddrive/share/TV3b9rQxEvMwKww9XAisoeS7M72Xj78GccrkR6VzZsi

The Collider doesn’t produce the nice faults for fabric, but it creates a much better working condition for the fabric.

I love that a lot. Thanks for sharing.

Screen capture
https://www.amazon.com/clouddrive/share/bNIXABhUtrre6j37hrktpEsR3uh6NeFBSu467djbXe8
Check out the file 02 and 03! Restore Shape: in out

Cheers

P.S.: I have send you a link with an idea. It might need some tweaking of course.

For very difficult cases… as we have seen above, when thin fingers can’t be captures easily. I had the idea of a intermediate layer, and Alex suggested the Collision Deformer. HEre is the conclusion:

The idea is to have a flat object connected to the index finger joint of each hand and one to the tip joint of the head. Each time only via x and z only. So the y position can be adjusted. In this way these three critical points look now more like a fresh dough of a pizza round had landed while not closing down completely, bell-like, but adaptive to the movement. This helps the fabric in a great way.

A little example:
Screen capture and scene files
https://www.amazon.com/clouddrive/share/ku6yNrke1MuZDESiNOPGcuag4Zlss1ftmAVdUYSoSfD

The sphere size is on purpose very small or very large, anyone it helps to set up quickly a partial or complete “Collision Surrogate”.

ENJOY.