Use Houdini Like Marvelous Designer?

[Atom]

Hi All,

I have been playing around with Marvelous Designer trying to learn how to make clothes. In MD you draw planes, link edges to form constraints and the simulation engine will draw the edges together and wrap the planes around a collision object.

 

I thought this might be possible in Houdini but I can't seem get the setup to work. When I set the cloth constraint to Soft and increase the Stiffness I see no effect of seams being drawn together. The Stiffness parameter seems to have no effect. I have tried values from 0 to one million and the resulting simulation is always the same.

The tooltip claims that this is possible. "...this controls how quickly the corresponding stitch points will be drawn together.."

Am I expecting too much from Houdini?

Can Houdini draw two edges together that are spaced far apart?

I was using Dennis's posted example file in the CLOTH TO CLOTH thread for this test.

ds_constrain_clothToCloth_example_v01.hipnc

Edited May 29, 2016 by Atom

[Guest tar]

Stitch Cloth shelf tool does this.

[DennisSchmidt]

If you come up with a solution i would be interested. I have been trying it myself with no luck. The setup was created manually without the shelf tool. Although i tried setting it up with the shelf tool as i might be missing something. Still the same.
In the cloth masterclass at around 56:30 the soft mode works. Maybe it's because of the new finite element solver? The old cloth solver doesn't seem to work anymore.
Further i tried the SBD pin constraint and it works as expected. But the SBD spring constraint behaves just like the soft mode from the cloth stich(not working).

[Guest tar]

I'm not understand the issue as using the shelf tool works? see attached.

ClothStitch.hiplc

[DennisSchmidt]

It works with the type of the stich constraint set to hard. The only "problem" is that it snaps on the first sim frame. When switching to the soft type there is no effect. The tooltip says " Whether to use a hard constraint or a soft constraint. Hard constraints are always enforced exactly. The soft constraints create forces instead."
In the cloth masterclass you can see that when the type is set to soft it snaps over time and when set to hard it happens in one frame.

[Atom]

Thanks Marty,

That is close to what I am trying to do. When I supply an alternate collision object, such as a cylinder, the cloth still keeps a square shape instead of wrapping around the cylinder. I also see warnings inside the AutoDOP network too.

 

I am new to cloth so I am not really sure of the exact workflow. I have watched the masterclass Dennis mentions.

 

 

ap_ClothStitch.hiplc.hipnc

[Guest tar]

@Atom You can use the Deforming cloth shelf tool on the new cylinder - in this example make sure cylinder is smaller than the cloth sheets or it gets jumpy. 

 

@DennisSchmidt That's the older and more featured H12 cloth solver - send it in as a bug report to SideFx.

[Atom]

@Marty, that would work in this simple case of making a pillow but when I try to make a shirt I run into even more problems. Setting aside the fact that it is incredibly tedious to select all those points along an edge. After I make my selections, and I am careful to select the points from top to bottom or left to right, I still end up with cross-stiching which I don't know how to resolve?

What would be more convenient would be an additional tool "Stich By Edge" instead of stitch by point. This imaginary "Stich By Edge" tool would look at all the points in the source edge and all the points in the target edge and generate the appropriate point list for the constraint.

ap_make_shirt.hipnc

[Guest tar]

I wouldn't replicate MD approach as it's limited for vfx work - you could model and sculpt a t-shirt in Zbrush, or wherever,  and then just make into cloth, adding stiffness and other attributes.

 

The cloth constraints takes point groups - you can see that in my pillow example.

 

 

[Atom]

I guess what is disappointing is that the A-KEY option for selecting a row of points does not work with the Stitch tool. You have to manually select every single point on the cloth object. Because the cloth object has to be subdivided to begin with this means a lot of selection just to get points along an edge. And because the groups are directly linked to point numbers you can't subdivide your cloth later or your stitch points will be off.

I still have not completed the entire Marvelous Designer To Houdini loop. I was wondering how Houdini would handle an object that already has folds embedded into it. I could still make a Marvelous Designer exported object into a cloth object in Houdini right? Then Houdini would flatten out and re-sim my simulated cloth. The same thing would happen if I used z-brush as well, right? I only ask because I am not really a modeler or a sculptor so MD offers a way for me to make clothes fairly easy as a non-artist.

What would be the point in sculpting folds in z-brush only to have them "simmed" back out in Houdini when you make it a cloth object for your character? I don't know a lot about z-brush so I am wondering about the entire cloth from one program to the next workflow.

[Guest tar]

Use the implicit creation of groups, via unshared edges, bounding object etc. Explicit point group creation is not the best choice when going into sims.

Cloth Proxy shelf tool takes sims with lower res geo then transfers that to a high res mesh. 

So-called folds are just geometry, nothing special, just wack it into the cloth object and you are good to go. Try it!

The main advantage with MD is that it is a good bit faster than Houdini.  The disadvantage is that you have to build you sim meshes in it, as patterns and then sew it together.

 

[Guest tar]

52 minutes ago, Atom said:

I guess what is disappointing is that the A-KEY option for selecting a row of points does not work with the Stitch tool.

Can you Rfe that please. IIRC that is meant to be implemented at some point.

[Atom]

Thanks for the feedback, I see what you mean by using groups, it makes revisions a lot easier and I can use the A-KEY to get the edge selection right.

I did report the A-KEY stitch bug to SESI as well.

So here is my workflow so far.

• Create the garment shape as a polygon curve outline
• Use the divide node with convex off and bricker on to fill interior of the curve shape with faces
• Create groups along the edges of the shape where stitching where occur
• Copy and paste this filled shape to make the back side of the garment
• Dive inside of copy and rename the groups so their names reflect the back side (i.e. back_sleve_L etc...)
• Move the the front and back shapes some distance away from the collision object
• Use the shelf tool to convert the garment shapes into cloth objects
• Use the shelf tool to convert the collision object into a rigid collider
• Use the stitch tool and just pick a single point on each cloth object (this makes a single constraint node in the AutoDOP you can copy and paste later)
• Dive inside the AutoDOPNetwork and replace the point number on the constraint with the group names for the source and the target
• Copy and paste this constraint node and re-type the appropriate group names for each stitch on your garment
• Increase the uniform division of the collision guide to make sure the colliding object has enough volume to resist the cloth
• Add a little Offset Surface value to the collision object (0.005)
• Turn off gravity
• Go up to the top level and make sure the garment is not penetrating the collision object on frame 1 (translate garment if needed)
• Run the sim

This gets me close to the Marvelous Designer basic workflow. The garment jumps onto the collision object and deforms around the mesh.

I am still getting some penetration of the cloth into the collision object but that may be fixable by adjusting cloth settings. I still need to play around with that now that I have a garment in place.

 

ap_make_shirt.hipnc

[rayman]

I'm not a cloth expert, but as far as I know cloth solver works much better with geometry collisions, so you can turn off 'Use Volume Based Collision Detection' and control the amount of penetration using Thickness parameter.

 

Cheers!

[Atom]

Well it is kind of a toss up. The volume based collision works better for static modeling. As soon as I add animation to the collision mesh the volume based collision fails to work correctly, the cloth does not move with the mesh.

If I turn off volume based collision, the cloth kind of sinks into the collision mesh even though I have increased the offset. But the cloth does move with deforming geometry, kind of.

I still don't know how I could possibly make a shirt move with an animated character at this time.

[rayman]

I'm not sure about that - in my (simple) tests surface based collisions always worked better.

Check the attached file - I animated the geometry and cranked up some of the settings - it works well with no penetrations even without additional constraints. 

ap_make_anim_shirt.hipnc

[Atom]

Thanks for tinkering with my file. Your settings pass my bend test too.

It looks like, inside the Finite Element Solver, you increased Max Iterations Linear Solve up from 1024 to 10,000 and Max Collision Passes up from 2 to 8.

 

[Guest tar]

In general the min substeps should be 4-8 for cloth solves. 

[Atom]

Thanks Marty, nice to know.

[rayman]

I also tweaked the Static and Cloth objects Thickness parameters - the original ones were too small.

I think you can even return Max Iterations Linear Solve to default. I increased it only to prevent the warnings.