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Virtual World Dynamics F.A.Q (Last Updated: 2024 Sep 15 1:40 pm)




Subject: Tutorials for VWD


VirtualWorldDynamics ( ) posted Sun, 05 January 2020 at 5:10 PM · edited Thu, 05 September 2024 at 3:23 AM

Hello,

I prepared a few scenes for the tutorials.

I want to start them at the end of the week. Then I want to use all the following week to work on them.

My current problem is: what will be the starting point of these tutorials. I thought to do 2 or 3 very simple tutorials explaining the interface or the vertices selection.

After that, I would be interested to have your opinion to the next tutorials to do. Perhaps a tutorial on the two stiffening methods (extension and neighborhood).

A tutorial showing the use of the dynamic deformation can be very useful. I thought to show how to how to correct a sit pose and how to give a good volume to hair.

If you have some ideas, please, feel free to tell us.

____________________________________________

Follow me on Twitter : @VWDynamics

Watch demo videos on Youtube


creationz8 ( ) posted Sun, 05 January 2020 at 8:43 PM

Any tutorials you do explaining the use of the settings would be a great start. Your software, to me, is not just a "simple" software because it has a lot of features that enhances its potential and I am eager to learn more and push its limits.


zanth77 ( ) posted Mon, 06 January 2020 at 7:00 AM · edited Mon, 06 January 2020 at 7:02 AM

Stiffening options is good, especially after import. In v1, you could select vertices and 'rigidify' by neighborhood or extension. However I never understood if this was just replacing the 'extended stiffness' options from import dynamic params (also labeled neighborhood/extension) or what. Regardless, I still haven't found a way to make something VERY stiff while still letting it be affected by gravity (e.g., buttons, belt buckles).

Another problem I have is self-intersection. I usually have self-collision turned off to make the sim faster, but even when I turn it on, I still tend to get areas where the mesh overlaps itself a bit. Ways to prevent this would be cool. I'm sure I could figure it out if I played with stuff like detection distance, etc more.

Reset sim -- Is there a way to accomplish this? I know you can go into sim history and regenerate the entire scene, but re-importing everything seems like overkill when you just want to reset back to the beginning by removing the sim-created morphs.

Params! This one is huge. The pdf has technical explanations of everything. It would be cool to have 'practical explanations'. For example in dynamic params we have stretch, softness and node weight. I NEVER alter these from the default. The pdf shows some technical stuff, but that's it. What I'd like in the tutorial is real life stuff like - 'See how this dress goes flat like a bedsheet after sim? Want it to retain a bit more of its original shape (folds etc), simply change stretch/softness/weight to xyz.' I know I'm just making stuff up, but you get the point. Clothing going 'flat' is a real-life problem I have with VWD (dForce tends to maintain dress pleats, etc better by default), so showing how I can mess with params to solve a real-life problem would be HUGE (for this specific problem, maybe I need to mess with rigidity instead, not sure). So a common problem/solution approach would be ideal for me and I suspect many users. Here are some other common problems:

  • How to maintain clothing thickness? (vert neighborhood probably solves this, but can maybe show how to do a sim where only edges are neighborhood since extension is usually more memory efficient in general).
  • How to prevent bunching/over-stretching in a dynamic sim? (I often do dyn sims for send-pose-to-host (instead of send anim to host) solely to get the best fit for a pose. Often as the figure is moving, I'll notice areas of over-bunching or stretching in cloth mid-sim. I pause it, but SHIFT doesn't work (at least in v1) until entire sim is done, so no good way to let the cloth catch-up. I usually make do by increasing/decreasing gravity/inertia but suspect I could play with sub samples, iterations, etc params to get a better effect).
  • How to avoid bedsheet flatness when desired. Just a repeat of above. All comes down to rigidity I'm sure. Showing an example for hair too would be cool. Curly/wavy hair is hard. Let's say character is bending forward. Sometimes I'll 'fix' the scalp and upper part of the hair. I can make the dangling hair parts rigid enough to look ok but the transition point between the fixed area and the hanging parts looks too extreme. I haven't really solved this problem in VWD yet. I usually just solve it in an external paint program. But if I think about it, I could probably play with decreasing rigidity for the hair as it goes from center scalp outwards and down the sides, or something like that.

These are just a few ideas. I'm sure there are tons of others, but wanted to mention some in case you were looking. Tutorials take time and time is money, so I'm not expecting practical examples of every problem/scenario (that would likely be impossible anyway), but wanted to mention some just in case you needed a pool to pull from (and more importantly, to illustrate how explaining the params in a real-world problem-solution example format would be most helpful).

Overall, I love VWD and am looking forward to upgrading to v2 once I can afford it. Thanks for creating it!


creationz8 ( ) posted Mon, 06 January 2020 at 8:59 AM

Zanth77 said it like a pro. and I second everything said above.


VirtualWorldDynamics ( ) posted Mon, 06 January 2020 at 3:43 PM

Hello creationz8 and zanth77,

thank you for your precise messages.

I agree with you, the stiffening is the highest priority. I will try to explain it clearly. Perhaps in several tutorials.

About the resetting of the scene, I wanted to do it but I had some difficulties. particularly, memory loss. I will come back to it again to find a good solution to this problem.

About the rigidification of the hair, the hair assistant offers a very efficient method to do that, by using a soft transition. I will do a tutorial to show the result.

This thread can be used to show the errors you have in the program. I suppose many users will have the same issues. You can send an image showing the result you have and explaining the result you would like to have. This way will be a very good starting point to create a tutorial.

____________________________________________

Follow me on Twitter : @VWDynamics

Watch demo videos on Youtube


zanth77 ( ) posted Mon, 06 January 2020 at 6:46 PM

Thanks!

I wouldn't call them errors, just scenarios that folks might want to handle. For example, I just ran a sim where Gen8 figure went from default to sitting pose in 60 frames. In VWD, I managed to fix the 'cloth bunching' issue by nailing the top half of the dress to collision object so it followed the figure during the sim.

I also turned on self-collision which fixed most of the self-collision issues but still left a few areas which appear in Daz Texture Shaded mode as black (see screen shot). This may or may not impact rendering (depends on the shader). The fix in this example would've been to use Shift-Mouse-Left-Click to pull the cloth out of itself. However perhaps there are params I could've adjusted better to make the self-collision detection more stringent?

A third problem I had (and often have) in this example is too much stretch. I always turn off inertia/grav and press SHIFT for a few seconds at the beginning to handle the initial puff-out of the cloth (thanks for this tip btw!). However, the cloth tends to get about 5% bigger. I usually remedy by scaling the cloth to 95% but perhaps I should try playing with stretch/softness for selected areas instead? I don't mind the 5% growth in the lower part of the dress, but up around the chest (in this example), I prefer it to hug the body as it did before sim. Fixed verts option is perfect if the sim isn't dynamic, but the option is of course unusable if it is dynamic. Nail to collision works great but still get 5% loosening. Now that I think about it, once I learn the advanced rigidify techniques, it may resolve this issue too for me (assuming it plays nice with nailing to collision). Otherwise, learning the difference between scaling to 95% and altering stretch/softness as possible methods to solve this example (or when you'd use one or the other or both to solve various situations) would be helpful.

Collision1.jpg


VirtualWorldDynamics ( ) posted Tue, 07 January 2020 at 4:03 PM

OK I see what kind of tutorial you would like to have. I will start a tutorial showing how I try to simulate the image you show.

Sometimes, the self-collision does not manage to pull the vertices correctly because the penetration is too strong (deep). The dynamic deformation allows to correct the cloth. when the cloth begin to have a correct shape, the self-collision restart working fine. Then, you can leave the simulation finalize the correction and the result will be really good..

I sent you a sitemail.

____________________________________________

Follow me on Twitter : @VWDynamics

Watch demo videos on Youtube


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