# Daz 3D Introduces dForce Physics Engine

• Posts: 82,462

And for fun here is the ngon cube (each side is one polygon) - at least it's gone below the ground plane :)

• Posts: 18,956
Chohole said:

Your plane isn't terally as plane - its edges have cery dense geometry, each loop separated by 0.5mm. I suspect its the interaction of those tightly packed loops that is driving the odd behaviour.

heh      love this explanation

If the vertical edges on the sides of the squished cube are shorter than the Collision Offset for the surface that those edges participate in, the collision/repulsion iterations are going to move the second-order neighbors away from each other (and generate a certain amount of force/energy), in order to satisfy the specified offset. On the subsequent sim iteration, the engine is going to attempt to resolve the edge length of those (now stretched) edges and generate a certain amount/direction velocity. The subsequent collision/repulsion iterations are going to repeat their previous task... so on and so forth. All of that built up energy must go somewhere... so off it flies.

Hmm. Sounds like a Robism.

• Posts: 2,932
Chohole said:

If the vertical edges on the sides of the squished cube are shorter than the Collision Offset for the surface that those edges participate in, the collision/repulsion iterations are going to move the second-order neighbors away from each other (and generate a certain amount of force/energy), in order to satisfy the specified offset. On the subsequent sim iteration, the engine is going to attempt to resolve the edge length of those (now stretched) edges and generate a certain amount/direction velocity. The subsequent collision/repulsion iterations are going to repeat their previous task... so on and so forth. All of that built up energy must go somewhere... so off it flies.

So in the DS world, Michael the unsuspecting digital scientist is hit by a flying self-propelled flattened cube from below, and so discovers their local law of antigravity.

• Posts: 5,116

In general dynamic cloth systems are designed for the cloth to not have actual modelled thickness. You are adding another level of complexity by having modelled thickness as the inner layer will be colliding with the figure and then the outer layer will be colliding with the inner layer (assuming self-collision is turned on). Cloth systems can be unstable at times, if for instance the cloth is trapped under the arm or if a hand gets too close to the body (the cloth will try to maintain a minimum distance from any surfaces, but in such cases, it has nowhere to go). Having double layered clothing just adds to the potential issues.

• Posts: 10,634
Chohole said:

If the vertical edges on the sides of the squished cube are shorter than the Collision Offset for the surface that those edges participate in, the collision/repulsion iterations are going to move the second-order neighbors away from each other (and generate a certain amount of force/energy), in order to satisfy the specified offset. On the subsequent sim iteration, the engine is going to attempt to resolve the edge length of those (now stretched) edges and generate a certain amount/direction velocity. The subsequent collision/repulsion iterations are going to repeat their previous task... so on and so forth. All of that built up energy must go somewhere... so off it flies.

So in the DS world, Michael the unsuspecting digital scientist is hit by a flying self-propelled flattened cube from below, and so discovers their local law of antigravity.

LOL

• Posts: 2,412
Chohole said:

Your plane isn't terally as plane - its edges have cery dense geometry, each loop separated by 0.5mm. I suspect its the interaction of those tightly packed loops that is driving the odd behaviour.

heh      love this explanation

If the vertical edges on the sides of the squished cube are shorter than the Collision Offset for the surface that those edges participate in, the collision/repulsion iterations are going to move the second-order neighbors away from each other (and generate a certain amount of force/energy), in order to satisfy the specified offset. On the subsequent sim iteration, the engine is going to attempt to resolve the edge length of those (now stretched) edges and generate a certain amount/direction velocity. The subsequent collision/repulsion iterations are going to repeat their previous task... so on and so forth. All of that built up energy must go somewhere... so off it flies.

That makes perfect sense. Is there a setting that would make the software ignore the initial positioning of the scale? Or would that be too complex?

• Posts: 2,882
Chohole said:

Your plane isn't terally as plane - its edges have cery dense geometry, each loop separated by 0.5mm. I suspect its the interaction of those tightly packed loops that is driving the odd behaviour.

heh      love this explanation

If the vertical edges on the sides of the squished cube are shorter than the Collision Offset for the surface that those edges participate in, the collision/repulsion iterations are going to move the second-order neighbors away from each other (and generate a certain amount of force/energy), in order to satisfy the specified offset. On the subsequent sim iteration, the engine is going to attempt to resolve the edge length of those (now stretched) edges and generate a certain amount/direction velocity. The subsequent collision/repulsion iterations are going to repeat their previous task... so on and so forth. All of that built up energy must go somewhere... so off it flies.

That makes perfect sense. Is there a setting that would make the software ignore the initial positioning of the scale? Or would that be too complex?

You're trying to give the water "thickness," correct?

Maybe applying/adding a push modifier after applying the drape.  I know both smoothing and push modifiers don't work before/durring the simulation, but I've successfully applied both afterwards.

• Posts: 82,462
Chohole said:

Your plane isn't terally as plane - its edges have cery dense geometry, each loop separated by 0.5mm. I suspect its the interaction of those tightly packed loops that is driving the odd behaviour.

heh      love this explanation

If the vertical edges on the sides of the squished cube are shorter than the Collision Offset for the surface that those edges participate in, the collision/repulsion iterations are going to move the second-order neighbors away from each other (and generate a certain amount of force/energy), in order to satisfy the specified offset. On the subsequent sim iteration, the engine is going to attempt to resolve the edge length of those (now stretched) edges and generate a certain amount/direction velocity. The subsequent collision/repulsion iterations are going to repeat their previous task... so on and so forth. All of that built up energy must go somewhere... so off it flies.

That makes perfect sense. Is there a setting that would make the software ignore the initial positioning of the scale? Or would that be too complex?

You can edit the offset value in the Surfae settings - I hadn't mentione dit as it seemed that a value small enough to avoid the anti-gravity would be small enough to cause other issues.

• Posts: 131
edited November 2017

I was asked for more information due to my post about not being able to use Dforce on a Genesis 3 character using Genesis 3 clothes, so I took a series of screen shots to show the problem.  In the first frames it shows a stock Genesis 3 character with a Genesis 3 dress conformed to it.  After adding the Dforce modifier and running the simulation, the dress explodes.  However, in the next frames it shows a Genesis 8 character with the same Gemesis 3 dress conformed to it and the simulation runs fine and the dress drapes pretty good.  In both of these test I have not changed the simulation settings under the surfaces tab.

• Posts: 82,462

I was asked for more information due to my post about not being able to use Dforce on a Genesis 3 character using Genesis 3 clothes, so I took a series of screen shots to show the problem.  In the first frames it shows a stock Genesis 3 character with a Genesis 3 dress conformed to it.  After adding the Dforce modifier and running the simulation, the dress explodes.  However, in the next frames it shows a Genesis 8 character with the same Gemesis 3 dress conformed to it and the simulation runs fine and the dress drapes pretty good.  In both of these test I have not changed the simulation settings under the surfaces tab.

It may be that the chnage after AutoFit is fixing a mesh issue - what happens if you just load the dress into a scene with nothing but a ground plane primitve and simulate it?

• Posts: 131

I was asked for more information due to my post about not being able to use Dforce on a Genesis 3 character using Genesis 3 clothes, so I took a series of screen shots to show the problem.  In the first frames it shows a stock Genesis 3 character with a Genesis 3 dress conformed ot it.  After adding the Dforce modifier and running the simulation, the dress explodes.  However, in the next frames it shows a Genesis 8 character with the same Gemesos 3 dress conformed to it and the simulation runs fine and the dress drapes pretty good.  In both of these test I have not changed the simulation settings.

I was asked for more information due to my post about not being able to use Dforce on a Genesis 3 character using Genesis 3 clothes, so I took a series of screen shots to show the problem.  In the first frames it shows a stock Genesis 3 character with a Genesis 3 dress conformed to it.  After adding the Dforce modifier and running the simulation, the dress explodes.  However, in the next frames it shows a Genesis 8 character with the same Gemesis 3 dress conformed to it and the simulation runs fine and the dress drapes pretty good.  In both of these test I have not changed the simulation settings under the surfaces tab.

It may be that the chnage after AutoFit is fixing a mesh issue - what happens if you just load the dress into a scene with nothing but a ground plane primitve and simulate it?

I'll try that but this happens with any Genesis 3 dress that I try to drape with Dforce on a Genesis 3 female, and that is the whole idea.

• Posts: 131

I was asked for more information due to my post about not being able to use Dforce on a Genesis 3 character using Genesis 3 clothes, so I took a series of screen shots to show the problem.  In the first frames it shows a stock Genesis 3 character with a Genesis 3 dress conformed ot it.  After adding the Dforce modifier and running the simulation, the dress explodes.  However, in the next frames it shows a Genesis 8 character with the same Gemesos 3 dress conformed to it and the simulation runs fine and the dress drapes pretty good.  In both of these test I have not changed the simulation settings.

I was asked for more information due to my post about not being able to use Dforce on a Genesis 3 character using Genesis 3 clothes, so I took a series of screen shots to show the problem.  In the first frames it shows a stock Genesis 3 character with a Genesis 3 dress conformed to it.  After adding the Dforce modifier and running the simulation, the dress explodes.  However, in the next frames it shows a Genesis 8 character with the same Gemesis 3 dress conformed to it and the simulation runs fine and the dress drapes pretty good.  In both of these test I have not changed the simulation settings under the surfaces tab.

It may be that the chnage after AutoFit is fixing a mesh issue - what happens if you just load the dress into a scene with nothing but a ground plane primitve and simulate it?

I'll try that but this happens with any Genesis 3 dress that I try to drape with Dforce on a Genesis 3 female, and that is the whole idea.

As I thought the dress just falls to the ground plane, because it does not have to interact with a G3 figure.

• Posts: 10,712
edited November 2017

Posted in case somebody else has the same problem:

I encountered a problem with dForce when upgrading to DS 4.10 from DS 4.9 on one of machines. The 'Add dForce modifier' items did not appear in Edit > Object > Geometry. After much tearing out hair, reinstalling DS 4.10, rebooting the computer, etc. I found the solution was to change my Self Serve' layout to a different one (City Limits). The 'Add dForce modifier' items then showed up. Next I changed the layout back to Self Serve and the items still were present in Edit > Object > Geometry.

EDIT: I just saw in another thread I could have solved this easier by running Window > Workspace > Update and Merge Menus script.

Post edited by Charlie Judge on
• Posts: 9,476

I was asked for more information due to my post about not being able to use Dforce on a Genesis 3 character using Genesis 3 clothes, so I took a series of screen shots to show the problem.  In the first frames it shows a stock Genesis 3 character with a Genesis 3 dress conformed to it.  After adding the Dforce modifier and running the simulation, the dress explodes.  However, in the next frames it shows a Genesis 8 character with the same Gemesis 3 dress conformed to it and the simulation runs fine and the dress drapes pretty good.  In both of these test I have not changed the simulation settings under the surfaces tab.

It is unclear from your screenshots, so please be patient with me. Have you tried running the sim with the Use Memorized Pose option? (I'm also doing this from memory, so the actual name of the parameter may be somewhat different.)

• Posts: 6,869
edited November 2017

Evening Gown simulated on Genesis 3 Female.

https://www.daz3d.com/evening-gown-for-genesis-3-females

Post edited by Artini on
• Posts: 131
edited November 2017

I was asked for more information due to my post about not being able to use Dforce on a Genesis 3 character using Genesis 3 clothes, so I took a series of screen shots to show the problem.  In the first frames it shows a stock Genesis 3 character with a Genesis 3 dress conformed to it.  After adding the Dforce modifier and running the simulation, the dress explodes.  However, in the next frames it shows a Genesis 8 character with the same Gemesis 3 dress conformed to it and the simulation runs fine and the dress drapes pretty good.  In both of these test I have not changed the simulation settings under the surfaces tab.

It is unclear from your screenshots, so please be patient with me. Have you tried running the sim with the Use Memorized Pose option? (I'm also doing this from memory, so the actual name of the parameter may be somewhat different.)

Yes, I tried that..., thats the setting in the Simulation tab, under simulation.. start bones from memorized pose...  However I'm a little unclear as to what "Memorized Pose" it is referring to, the one that you create by right clicking on the parameters tab and selecting "Memorize.. Memorize Figure Pose" or something else??

• Posts: 901

i'm not sure what i'm doing wrong but 80% of what I try explodes durring simulation after a few seconds. I figured it was old items, so i bough the dforce ruffle dress this morning and after a few frames, it also explodes... this is very frustrating.

Im on a mac, the scene is empty and i'm on the latest version of OSX with the latest drivers..

Now i don't even find the ruffle dress in the store.... is it broken?

Try adjusting the damping on the two of the dress' surfaces (go to the Surfaces pane's Editor tab, click to expand the dress in the list on the right, and select Trim Skirt and Lace Bottom, then alt-click (opt-click for a Mac) on the Damping slider to reset its value (you can use the text box at the top of the pane as a filter to make finding the slider easier)..

Wow thank you! I had a problem with the same dress. Is there a possibility there will be an update for this dress that fixes this?

• Posts: 82,462

I was asked for more information due to my post about not being able to use Dforce on a Genesis 3 character using Genesis 3 clothes, so I took a series of screen shots to show the problem.  In the first frames it shows a stock Genesis 3 character with a Genesis 3 dress conformed to it.  After adding the Dforce modifier and running the simulation, the dress explodes.  However, in the next frames it shows a Genesis 8 character with the same Gemesis 3 dress conformed to it and the simulation runs fine and the dress drapes pretty good.  In both of these test I have not changed the simulation settings under the surfaces tab.

It is unclear from your screenshots, so please be patient with me. Have you tried running the sim with the Use Memorized Pose option? (I'm also doing this from memory, so the actual name of the parameter may be somewhat different.)

Yes, I tried that..., thats the setting in the Simulation tab, under simulation.. start bones from memorized pose...  However I'm a little unclear as to what "Memorized Pose" it is referring to, the one that you create by right clicking on the parameters tab and selecting "Memorize.. Memorize Figure Pose" or something else??

Yes, on a freshly loaded figure that will often be the zero pose (though it doesn't have to be). Memorise Pose works by locally changing the default values for the joint rotations.

• Posts: 9,476
edited November 2017

I was asked for more information due to my post about not being able to use Dforce on a Genesis 3 character using Genesis 3 clothes, so I took a series of screen shots to show the problem.  In the first frames it shows a stock Genesis 3 character with a Genesis 3 dress conformed to it.  After adding the Dforce modifier and running the simulation, the dress explodes.  However, in the next frames it shows a Genesis 8 character with the same Gemesis 3 dress conformed to it and the simulation runs fine and the dress drapes pretty good.  In both of these test I have not changed the simulation settings under the surfaces tab.

It is unclear from your screenshots, so please be patient with me. Have you tried running the sim with the Use Memorized Pose option? (I'm also doing this from memory, so the actual name of the parameter may be somewhat different.)

Yes, I tried that...  However I'm a little unclear as to what "Memorized Pose" it is referring to, the one that you create by right clicking on the parameters tab and selecting "Memorize.. Memorize Figure Pose" or something else??

No. I'm sorry. I've since found the exact wording: Start Bones From Memorized Pose. This is one of the Global Properties in the Simulation Settings tab.

This is from the official Start Here thread:

• Start Bones From Memorized Pose
• Type: Bool
• Default Value: true
• Notes:
• Describes whether or not the simulation should start from the “memorized pose” of articulated objects (i.e., figures) in order to address cases where complex poses adversely affect the starting shape of the simulated object such that it will not provide realistic results when simulated
• When enabled, articulated objects that are participating in the simulation will begin in their respective default poses and gradually move into their respective target poses, allowing the simulation to better represent the original dimensions of the simulated object

You can schlog through the whole section on Global Properties here: https://www.daz3d.com/forums/discussion/203081/dforce-start-here#global_properties

Believe me, the more you work with dForce, the more sense the official thread will make. (Well, it was true for me, anyway.)

ETA: I reread you comment. Arrgh... need more coffee. Okay, the "Memorized Pose" will be the T-Pose for G3 or the A-Pose for G8, unless you've actually used the Memorize Pose feature, which I don't recommend you use at this point,

• Posts: 131

I was asked for more information due to my post about not being able to use Dforce on a Genesis 3 character using Genesis 3 clothes, so I took a series of screen shots to show the problem.  In the first frames it shows a stock Genesis 3 character with a Genesis 3 dress conformed to it.  After adding the Dforce modifier and running the simulation, the dress explodes.  However, in the next frames it shows a Genesis 8 character with the same Gemesis 3 dress conformed to it and the simulation runs fine and the dress drapes pretty good.  In both of these test I have not changed the simulation settings under the surfaces tab.

It is unclear from your screenshots, so please be patient with me. Have you tried running the sim with the Use Memorized Pose option? (I'm also doing this from memory, so the actual name of the parameter may be somewhat different.)

Yes, I tried that...  However I'm a little unclear as to what "Memorized Pose" it is referring to, the one that you create by right clicking on the parameters tab and selecting "Memorize.. Memorize Figure Pose" or something else??

No. I'm sorry. I've since found the exact wording: Start Bones From Memorized Pose. This is one of the Global Properties in the Simulation Settings tab.

This is from the official Start Here thread:

• Start Bones From Memorized Pose
• Type: Bool
• Default Value: true
• Notes:
• Describes whether or not the simulation should start from the “memorized pose” of articulated objects (i.e., figures) in order to address cases where complex poses adversely affect the starting shape of the simulated object such that it will not provide realistic results when simulated
• When enabled, articulated objects that are participating in the simulation will begin in their respective default poses and gradually move into their respective target poses, allowing the simulation to better represent the original dimensions of the simulated object

You can schlog through the whole section on Global Properties here: https://www.daz3d.com/forums/discussion/203081/dforce-start-here#global_properties

Believe me, the more you work with dForce, the more sense the official thread will make. (Well, it was true for me, anyway.)

ETA: I reread you comment. Arrgh... need more coffee. Okay, the "Memorized Pose" will be the T-Pose for G3 or the A-Pose for G8, unless you've actually used the Memorize Pose feature, which I don't recommend you use at this point,

I have now tried many of the other dress outfits that I have for G3 and I'm going to have to admit that quite a few of the other dresses DO infact work with G3.  So I guess I will have to test each one and then somehow identify which ones work with the G3 female character.  But I still don't know why this dress WILL work with a G8 character but not with G3! Perhaps something with the bones...

• Posts: 1,065
carrie58 said:

Anyone know what's going on here? I have a G3F figure which uses Cayman Studios V4 legacy UV mappings for G3F. The skirt drapes ok, but does not collide with the hip and leg somehow, which results almost in a breach of modesty for the poor girl. Delete the all legacy surfaces, which I think are implemented as LIEs (?), and the skirt draps just fine, as expected. I've tried selecting the legacy items and adding a 'static surface' modifier - makes no difference. This happens with a range of clothing, not just this, so it's clearly some sort of systemic issue with this legacy UV mapping approach... The figure and skirt positions and all settings are identical for both these simulations - the *only* difference is that I deleted the Cayman legacy items in the latter drape - and it works fine...

CaymanStudio Legacy UV's use geografts and it was said somewhere there is a issue when using geografts .......

Yes, this is said to be fixed in a later build but you mightt ry switching to the Geometry Editor or Node Weightmap Paintbrush tool while draping (it may look funny as it shows the hidden geometry, but you can switch to another tool to render).

Thanks. There is a workaround, at least in this case, which is simply to delete the geografts, do the drape, then restore the figure from a previous save (or maybe even with 'undo' - haven't tried that). It works, just a bit clunky. They are only for UV mapping, so the shape is identical.

I have just had a go at this.  For some reason the free Bardot Outfit explodes like crazy on my system, whether I have the geografts or not.  But using Aave Nainen's Gored Dress I can see that in the Beta (4.10.0.113) the geograft issue seems to have been resolved, as Richard says.

Otherwise you can just run the simulation without the geografts then run the Legacy UV scripts afterwards.

• Posts: 2,882
edited November 2017

I know everyone's been thrilling about using dForce to make clothes.

I used it to make a tent. (inspired by a Mongolian ger)

The walls and roof were draped and then exported and re-imported.  The door is still dForce Dynamic.

(Yes, it still needs textures)

Post edited by DaWaterRat on
• Posts: 3,764

I know everyone's been thrilling about using dForce to make clothes.

I used it to make a tent. (inspired by a Mongolian ger)

The walls and roof were draped and then exported and re-imported.  The door is still dForce Dynamic.

(Yes, it still needs textures)

That looks great, really nice

• Posts: 3,398

Greetings,

Has anybody tried applying dforce to a bracelet, and then turning off nearly everything that makes it 'drape' so it's like a rigid obejct, but colliding with the character?  Is this even possible?

Similarly, could you take an apple model and drop it into a bowl of other fruit so it rests appropriately?

--  Morgan

• Posts: 82,462
CypherFOX said:

Greetings,

Has anybody tried applying dforce to a bracelet, and then turning off nearly everything that makes it 'drape' so it's like a rigid obejct, but colliding with the character?  Is this even possible?

Similarly, could you take an apple model and drop it into a bowl of other fruit so it rests appropriately?

--  Morgan

I ddi try in a beta, not the latest version, without success: making it too rigid gives the spring energy of the simulation nowhere to go and - in my tests - the mesh explodes.

• Posts: 5,116

I know everyone's been thrilling about using dForce to make clothes.

I used it to make a tent. (inspired by a Mongolian ger)

The walls and roof were draped and then exported and re-imported.  The door is still dForce Dynamic.

(Yes, it still needs textures)

I like that you found other creative uses for it - and the result looks great! It would have taken a long time to model all the folds and wrinkles by hand.

• Posts: 5,116
CypherFOX said:

Greetings,

Has anybody tried applying dforce to a bracelet, and then turning off nearly everything that makes it 'drape' so it's like a rigid obejct, but colliding with the character?  Is this even possible?

Similarly, could you take an apple model and drop it into a bowl of other fruit so it rests appropriately?

--  Morgan

Daz did say that this is the first application of dForce focused on clothing, which implies that they will be looking at other areas in the future and I am pretty sure that rigid body dynamics will be on their list!

• Posts: 335

Hello..I hate to ask..I'm sure this has been asked before. When I drape a skirt (older generations) the skirt just falls to the floor. I'm having trouble with weightmaps. Is there another way to add a simple achor and force the draping figure to drape without moving?

• Posts: 762
edited November 2017
magnumdaz said:

Hello..I hate to ask..I'm sure this has been asked before. When I drape a skirt (older generations) the skirt just falls to the floor. I'm having trouble with weightmaps. Is there another way to add a simple achor and force the draping figure to drape without moving?

Paint off the waist area of the skirt using the node weight map brush. Try to check if you could select the geometry/surface first.

CypherFOX said:

Greetings,

Has anybody tried applying dforce to a bracelet, and then turning off nearly everything that makes it 'drape' so it's like a rigid obejct, but colliding with the character?  Is this even possible?

Similarly, could you take an apple model and drop it into a bowl of other fruit so it rests appropriately?

--  Morgan

I ddi try in a beta, not the latest version, without success: making it too rigid gives the spring energy of the simulation nowhere to go and - in my tests - the mesh explodes.

How does the engine determine if an object is a rigid body or not? I tried applying the dforce:dynamic modifier to a bracelet and it gets deformed but refuses to slide down. It stays anchored to the wrist. Adding the same modifier to primitive objects (eg. cone, cube, sphere) does nothing and they're not even affected by gravity.

Post edited by y3kman on
• Posts: 6,869

Please also be aware, that older generations clothes (older than Genesis) are most likely not weight mapped.

You cannot paint weightmap on such clothes and converting them to weightmapped, not always works well.