Why does dForce suddenly just stop at a specific percentage

vijayasimhabr

Every now and then, I notice that the dForce Simulation simply stops, usually at a specific percentage. One time, I let it process over an entire night, and it was still stuck at that percentage.

Does not happen all the time. A specific pose seems to make it. Or, adding a specific dForce item. If I were to do dForce simulation 10 times (different clothing, hair or pose combination), this stucking thing seems to happen about 10 % of the time.

What am I doing wrong here? What can do to avoid this?

vijayasimhabr

Also, Daz stops responding on top of that. So, it's literally stuck. Like the whole process.

cgidesign

It happens in situations where the algorythm can't solve the collission of the vertices anymore. E.g. the pose of an arm says "bend by 90 degree". The settings of the cloth says be flexible and create folds accordingly. But to create those folds the algorythm thinks it must penetrate the cloth through the arm which is an invalid operation (this is a simplification but helped me to understand the issue). Dforce is then calculating a long time and in the end the cloth geometry is exploding (it can take really long till that happens). You can either wait for the explosion or just kill DS with the task manager.

Those situations can't be avoided in all cases. But to my experience it helps to alter the simulation parameters of the surfaces. There are a lot of threads in the forum regarding this. Search with google like this (don't click the blue link but copy the whole line into google's search field):

dforce explode site:https://www.daz3d.com/forums

One tip: Set the hair of a figure invisible if you simulate cloth. It speeds up the simulation and might avoid some of the lock up / explosion situations.

vijayasimhabr

@cgidesign

Your explanation makes perfect sense even with my limited usage of Daz 3D. I have already been killing and restrating DAZ every so often. Also, some specific dFroce items seem to have more issues than others. So, I am now filled with buyers remorse because, its such a pain to watch, after hours, the simulation stuck at 10 % 

I will read up more on the provided search tips/threads. Thank you

I have already started making hair (and anything else that is not part of simulation) invisible to speed things up. Nevertheless thank you for that point. 

cgidesign

I feel your pain. It happens to me as well

One thing I noticed - but have not testet in a scientific way - is that high damping values increase lockups on my side.

At default it is 0.1 but 0.2 works for me as well. If I change to 0.3 or more the explosions start to happen more often.

But again that can be a coincidence.

Richard Haseltine

cgidesign said:

I feel your pain. It happens to me as well

One thing I noticed - but have not testet in a scientific way - is that high damping values increase lockups on my side.

At default it is 0.1 but 0.2 works for me as well. If I change to 0.3 or more the explosions start to happen more often.

But again that can be a coincidence.

Damping reduces the effectiveness with which dForce can diffuse the energy in the srpings (edges) that define the shape - diffusing the energy is how it solves the draping. If the energy builds up rather than diffusing through the mesh then you get explosions.

Phatmartino

@vijayasimhabr I'm curious to know if you're Simming from a memorized pose, or along a range of the timeline, or just static "current frame/pose"...

 

I used to avoid simming from a memorized pose because it seemed to take so much longer, like not knowing if it's frozen half the time slowness before eventually getting at least a reasonable GPU.

 

There are lots of situations (poses) that I might get a freeze/explosion from a static pose, where if I turn Start from Memorized Pose ON, it works because the final pose had created intersections before simulating that you may not be able to see in the armpits or really anywhere depending on the garment...

Let us know what your general mode of operations is along those lines, may be hope for that last purchase yet?

cgidesign

For me it depends on the pose and the clothing item.

If the pose is way off the default A or T pose (e.g. 90 degree bend, twist etc. of arms or legs) I expect to get explosions. Before sim I check if the cloth intersects or has extremly streched vertices (wireframe view). If there are either intersections or extreme polygon distortions I use a timeline animation. Usually this avoids explosions.

Sim time on my RTX 2080 Ti is usally 30 mins to one hour depending on complexity of pose, animation and clothing item. Sim time for a static pose is normally a few minutes.

vijayasimhabr

Folks,

Ton of suggestions. As of now, I am going to stick to tried and tested dForce items for the current work.

However, I will give into the above suggestions, and see what happens and report back.

Thank you as always, CGI, Phat and Rich.

vijayasimhabr

Folks

Update. So, I am back with the one of the hairs, dForce Fringe Hair, that has been the source of all my crashes.

1. Start Bones from Memorized Pose: On
1. Pose Transition Time : 1.0
1. Figure Wearing Anything Else : No. The only thing is the hair on the head.
1. Turned off the Environment As Usual.
1. Simple Sitting Pose without Any interference from Hands Or Anything.
1. I am not doing animations. Just static pose.

The simulation finished in a few minutes (perhaps 2 or 3 minutes) on an RTX 3060 12 GB. No crashes or freezes.

Also, I could not find the 'dampening' thing. Not sure where to find it. I will experiment with different poses and cloth and hair items and update you folks when it crashes.

Thank you.

vijayasimhabr

1. Start Bones from Memorized Pose: On
1. Pose Transition Time : 1.0
1. Figure Wearing  : dForce Fringe Hair. dForce Nightie 2 Items.
1. Turned off the Environment As Usual.
1. Pose with Hands near Hair.
1. I am not doing animations. Just static pose.

The simulation finished in in about 5 minutes on an RTX 3060 12 GB. No crashes or freezes. Took a little longer, but, it finished fine.

I dont understand. I tried the exact same thing few days ago (but not the exact pose) and Daz was constantly freezing.

I am beginning to think, perhaps it was a specific pose that was creating problems. Not the hair. Not the clothes. It sort of adds up to what you folks mentioned about angles leading to an explosion of math calculattions.

Going forward if Daz freezes with dForce, I will just try a different pose. I was incorrectly blaming the clothing and hair.

felis

If you have a pose where a limb, e.g an arm will pass through other body parts from default pose, and there is a risk that the dForce item can get trapped, you either need to set start from default pose to off, or use anumated timeline so you can avoid the limb going through other parts.

For that reason I always use timeline as it gives me better control of the simulation.

vijayasimhabr

felis said:

If you have a pose where a limb, e.g an arm will pass through other body parts from default pose, and there is a risk that the dForce item can get trapped, you either need to set start from default pose to off, or use anumated timeline so you can avoid the limb going through other parts.

For that reason I always use timeline as it gives me better control of the simulation.

1. Start with Default Pose Off
2. Use Animated Timeline.

I have noted these points for my future dForce related crash. Thank you.

cgidesign

The damping is in the surfaces pane.

A general explanation of dforce can be found here:

https://www.daz3d.com/forums/discussion/203081/dforce-start-here#latest

 

vijayasimhabr

@cgidesign

Thank you, as always.

I have added this to my notes diary.

I will also browse through the link, that you have linked.