May the dForce be with you (BTS #21) (Patreon)

dForce is the name of the physics engine used by Daz Studio, but interacting with it is nothing like in a video game. AAA game studios have pretty much nailed clothing physics on character models, whereas in Daz there is a whole lot of manual tweaking required. Recently, I had to use it twice for Ménage à Moi and one went relatively quick while the other did not.

For the Incident scene, I wanted airbags visibly deflating after the crash (as shown above). The first step was creating the airbags because no one makes any that I'm aware of. I created a simple sphere and used a white cotton shader to make it look close enough to real airbags.

When I was first setting up the scene, Rico wasn't there, but I left him in for this pic to show why. Complex objects clipping into a dForce object during simulation is problematic and, in this case, leads to an unnatural end result. So I ran the simulation first and added him after.

I was kind of amazed at how I ended up using mostly default settings on the airbags. All I changed was gravity to 0.3 to get the shape I wanted. I then copied the first airbag and moved it over to the passenger seat. The title of this post is a little phrase I say to myself before hitting Simulate because it usually doesn't go so smoothly.

For instance, the shirt on the handrail during the first erotic scene took hours to get right. If you ever wonder why some devs make the clothes instantly disappear during sex scenes, you're about to get a small glimpse of the process.

This pic is the final saved starting point, it took me hours of trial and error to get this right. First, the wall had to be pushed away from the shirt as it was preventing it from behaving correctly (the same reason I removed Rico above). Then I had to get the orientation right for the shirt to fall in a way that still looked good.

One of the odd quirks of dForce is thin objects may not behave correctly. During my first attempts, the shirt would hit the handrail and then fall through it. Adjusting the gravity and the angle of the shirt mostly fixed it, but I still had to do some final tweaks.

The next big hurdle was assembling everything together. Not only did the shirt have to interact with the wall, but the toilet seat as well. I had to set the simulation up so those pieces came to their final resting place without major clipping issues with the shirt. It would take more than these few screenshots to go over the whole process, just know its something that requires experience, luck, and patience to get a final result like this:

All of that work for something most people wouldn't look at twice (especially when they have the option to look at Kiersten's booty instead). So yeah, that's why most devs delete discarded clothes rather than deal with the hassle of disrobing and using dForce for the crumpled clothes. In the future, I'll probably stick to flat surfaces or find convenient ways to make clothes not visible to the camera (like I did in Fantasy Dating).