Help Needed - Some Intermediate PhysSim Questions

Support Particles and Physics Simulations
1

OK guys, I’ve been trying to get this to work right (or rather the way I want it to) for around a week now and I’m stuck. Blend file of a simplified version of what I’m going for is linked.

I’m modeling a ship and am having 2 particular issues.

First, I’m trying to get the Yard platforms (Platform just above the sails for sailors to stand on, simply called “plane” in the .blend) to sit properly askew on the masts, as if broken, but held up by the spike going through them. I figured it’d be rather easy to just model a platform, enable Rigid Physics, turn the masts and spike to passive collision objects and just drop the bloody thing. Apparently I was wrong. What I get is either the platform shooting off into space or just slowly drifting but never really falling. I’ve tried adjusting the inner and outer thickness of all objects in their collision properties. I’ve set the calculation to read the Final Meshes rather than the basic geometry.

Second, suspending rigid objects from cloth. That weird hoop going through the random hole in the sail thats not even bloody falling anymore…? When I DID have it working, It would fall and weigh down the sail as intended, but then pass through the sails mesh and fall into oblivion, leaving the sail to flap around like an epileptic fish. The EVENTUAL goal once I get everything working right is to put a grappling hook through a smaller hole around that location with a rope fastening it to the ship’s belays.

I’ve been watching so many tutorials on animating this stuff you’d think I could recite them from memory by now, but each tute generally only focuses on one thing, and usually it’s the simplest form of that thing. Which means, I can’t find anything on complex interactions BETWEEN different types of physics sims.

So basically, my questions on both topics are:

  1. What specifically am I doing wrong and why? (Please don’t just tell me “change x number to y”. I’m trying to understand these systems and how they work, so just throwing numbers isn’t helpful.")
  2. How - if possible - do I get it to work right?
  3. What (in current version of Blender) am I idiotically forgetting or totally overlooking that would probably make the end goal of my project far easier?
  4. Any tutorials I somehow missed that cover exactly these problems?

Assume that:
-This is going to be animated.
-There will be wide to closeup long takes in the animation. So just NOT animating the ring wont look right.
-Because of the planned detail where the closeups will be, the overall size of the model needs to stay as is if possible.
-Time is no factor. This is a personal project. So if I need to spend 9 hrs/frame baking or rendering or whatever to make it look RIGHT, so be it.

The Blend for anyone interested:
http://pasteall.org/blend/index.php?id=46673

BONUS QUESTION!!!
I’m not at this stage yet, but eventually will be so… With Smoke/Fire simulations, is it better to create several small smoke domains in different locations? Or to just make one big ass box for the domain and put all the smoke emitters in it?

Thanks in advance for any help you guys can give! And Happy Blending!

2

I seem to be repeating this quite a lot lately. For rigid body physics to work “properly” the scale of the objects should be 1. You need to apply the scale to your mast; to do this you need to remove the keyframes you have set and press Ctrl-A. This should solve your first problem. The origin of objects (orange dot) should be at the center of geometry or center of mass. The objects in a simulation should be at real world size; I don’t know much about sailing ships but a mast of 170 meters seems large.

For your second problem, for some reason rigid body objects sometimes get corrupted, which appears to be the case for the ring on the sail. You can see this when the object is selected but does not have a green outline. Just remove the physics from it and then add it back again.

Hope this helps.

3

I’ll give those a shot. Thanks Alan! I could swear I’d reset the scale, but perhaps I’d done it one of the times I closed without saving to restart trying to figure all this out.

As to the size of the masts, you’re probably right. I modeled initially in BU and switched over to Meters later because I’m an idiot. I was hoping not to resize everything, but if it might help, I’ll do it.

Glad to hear the problem is more “fix your damn workflow” than “blenders not working right”. I can fix me.

Cheers!