Pin Contraint Problem

Discussions about simulation, hair and cloth in SOFTIMAGE©
RichardCulver
Posts: 34
Joined: 07 Jan 2012, 18:21

Pin Contraint Problem

Post by RichardCulver » 16 Apr 2012, 15:13

When I try to connect my Ice tree like this in the docs:

Image

To my pinned cloth mesh here:
PinConst1.jpg
I get this:
PinConst2.jpg
I found this.

http://xsisupport.wordpress.com/2011/05 ... mment-2589

Not sure what it is for but has something to do with a Pin Constraint problem. Says to connect it like so:

Image

However when I do this the "get this point pos" node just turns red and the sim won't play.
PinConst3.jpg
As I suppose would be the case. But how did he disconnect it and have it still be green and I suppose work?

Anyways, just need to get this sorted because currently the Pin constraint does not seem to work.

Setting a distance value or any of the other settings does not fix the issue, but rather introduces other odd phenomena.
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xsisupport
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Location: Montreal Canada

Re: Pin Contraint Problem

Post by xsisupport » 16 Apr 2012, 15:53

You don't have to touch the innards of Syflex Pin unless you have an older version of Softimage, where Syflex Pin was missing the "get this.kine.global".

RE: your screenshot, you have Get PointPosition instead of Get this.PointPosition.
// Steve Blair
// "You're not a runner, you're just a guy who runs" -- my wife
//
// My Blogs: Arnold | Softimage

RichardCulver
Posts: 34
Joined: 07 Jan 2012, 18:21

Re: Pin Contraint Problem

Post by RichardCulver » 16 Apr 2012, 16:15

Right. Thanks. I have not touched the innards. The nodes in the screen shot are the nodes that are shipping with 2012. All I did was try to disconnect it.

However it is all moot. I am just trying to solve this issue which is the only reason I tried to open the compound in the first place.

The screen grabs on above are more important. Those show the problem. I have not tried to touch anything in any of the compounds. This is Syflex and SI out of the box and it is giving me these strange results. In fact I have never gotten the pin constraint to do anything as expected. It always wigs out.

What is it I am doing wrong? I have followed the manual as far as I can tell to the letter.

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xsisupport
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Location: Montreal Canada

Re: Pin Contraint Problem

Post by xsisupport » 16 Apr 2012, 16:36

I built a similar set up without problem, but it can be finicky.

Don't use the SyflexI nodes, those are internal nodes. Prefer the nodes like Syflex Collide Mesh.
// Steve Blair
// "You're not a runner, you're just a guy who runs" -- my wife
//
// My Blogs: Arnold | Softimage

RichardCulver
Posts: 34
Joined: 07 Jan 2012, 18:21

Re: Pin Contraint Problem

Post by RichardCulver » 16 Apr 2012, 16:50

That's what I am using. For me here, it does not work at all. If I am doing something wrong, please someone point it out. I am doing as far as I know by the book and it looks more like a bug than finicky.

You say you've done this before. When? What version? Tried it lately with 2012? Working scene file? The one that ships with content does not use pinning.

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xsisupport
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Location: Montreal Canada

Re: Pin Contraint Problem

Post by xsisupport » 16 Apr 2012, 18:38

RichardCulver wrote:That's what I am using. For me here, it does not work at all. If I am doing something wrong, please someone point it out. I am doing as far as I know by the book and it looks more like a bug than finicky.

You say you've done this before. When? What version? Tried it lately with 2012? Working scene file? The one that ships with content does not use pinning.
Your screenshot shows you have a syflexICollideMesh node in your ICE Tree.
In general, don't use those lower-level nodes unless you have a good reason for it.

I just tried it in Softimage 2013.

You didn't mention what version you are using until your last post.

Update: Quick test in Softimage 2012:
http://xsisupport.files.wordpress.com/2 ... xample.png
// Steve Blair
// "You're not a runner, you're just a guy who runs" -- my wife
//
// My Blogs: Arnold | Softimage

RichardCulver
Posts: 34
Joined: 07 Jan 2012, 18:21

Re: Pin Contraint Problem

Post by RichardCulver » 16 Apr 2012, 19:05

xsisupport wrote: Your screenshot shows you have a syflexICollideMesh node in your ICE Tree.
In general, don't use those lower-level nodes unless you have a good reason for it.
xsisupport wrote: Prefer the nodes like Syflex Collide Mesh.

Hmmm... I think there is some confusion here.

Here is the screen shot from sample scene of a Syflex Tshirt that comes with SI. This scene works.

Isn't this exactly the same node as in the manual screen grab and my test scene?
Tshirt.jpg
My scene works also. Until I connect the Pin node.

That is the issue not the Collide Mesh.

I don't know of any other collide node to use and Collisions are not the problem.

If there is some node network you have with Pin working could you please share it as a grab? Or even the file so I can have a look?

Thanks.
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Last edited by RichardCulver on 17 Apr 2012, 10:15, edited 1 time in total.

RichardCulver
Posts: 34
Joined: 07 Jan 2012, 18:21

Re: Pin Contraint Problem

Post by RichardCulver » 17 Apr 2012, 10:06

I think the essence of this problem lies within the pin compound. The only way it works is if you have a mesh with the exact points set up. In other words a duplicate mesh. The sample scene file confirms this.

What is happening is the points are being told to get the point info and when that info is not the same they just wig out.

So the manual needs to be rewritten to reflect exactly what this node is used for and not used for. Much more specifically.

Currently there is no node that produces the effect you are looking for to pin cloth to a mesh for a character. I mean to say that this is a common set up for character cloth. And none of the constraint options are suitable even though the manual uses character as examples. It is not workable for animated characters in production.

In this scenario the two meshes are most always different.

What I was looking for was something like you have in Blender or LightWave. It is a common concept. And I even think it works the same way with Softimage Cloth. Basically you just need to assign points that hold a position. For a character, if you also have the cloth object driven by the bones, the pinned points will follow the bones while the remainder of the points get effected by cloth.

I could not figure out a way to set up a node network to have certain points follow a deformer such as a bone and the remaining points be affected by Syflex. I am not familiar enough with ICE yet. So I don't know how that is possible.

What I did find was that I could duplicate the part of the cloth mesh that would be pinned. Envelope that with the character bones. Then use a cluster on the cloth object to follw the exact points on the duplicate mesh with the Pin constraint. It works because now the pin constraint is looking for the points, finds and follows them in motion with the bones.

This is an odd work around. Certainly there is a more elegant solution.

I am not interested in Softimage Cloth for this set up. Only want this to work with Syflex.

Any ideas on how to set this up with Syflex on ICE?