Emitting sheets of paper with Cloth simulations

[lalleba]

Hello everyone!

I'm trying to achieve an effect with the use of Houdini where multiple sheets of paper is being blown out of an mailbox.(Mail and letters to be exact)

My plan is to use different layers of 3d sheets to comp together with some live action plates.

1. Some sheets are Rigid and doesn't fold or bend. This effect I've managed to achieve somewhat.

I found a hip file by Valerio Di Napoli where Rigid bodies are being emitted with the help of a particle network. By looking through this .hip I managed to understand the workflow somewhat and create my own RBD emitter.

Flipbooks of some test simulations ->youtu.be/f2L9kFGgAH4 My .hip file for this simulation is attached to the post.(RBDs_from_particleEmitter_v002.hip)

With some tweaking I think this approach could work as letters are quite stiff when they aren't opened and full of bills

One problem I have with this Is that I can't seem to use a grid as the instanced geometry. For reasons I can't understand, when I use a grid they just get stuck at the birth point of the particles and doesn't move at all.

As of right now I'm using a box scaled down in the Y axis to act as a letter.

2. Now on to my major problem! Some sheets I want to fold and swirl in the air. I would prefer them to interact with each other but its not must. By using a cloth simulation on a grid to create these sheets of paper works quite well and looks pretty good.

Since I don't need as many of these type of sheets, only about 10 or so, I'd like to think that the simulation would not be to expensive to preform? (If more sheets are needed I guess doing multiple simulations would be one way of approaching the problem to avoid performance issues.)

Now, I thought that the previous method of emitting RBD might be useful when trying to emitting these more dynamic sheets of paper. I was wondering if there is a way to use the same setup but instead of emitting Rigid bodies I want objects simulated as cloth to be emitted. Is this possible? I tried to just replace my RBD Point Object node with a Cloth Object node and the Rigid Body Solver node with a Cloth Solver node in my DOP network but with no success.

Attached a second .hip for this (CLOTH_from_ParticleEmitter_v001.hip)

trying to achieve something looking like this but emitting the papers from a specific spot.

I'm quite new to Houdini and don't really understand all the abbreviations yet so be gentle on me will ya! Haven't really caught up on the scripting part yet either. I would therefore prefer to solve this without much scripting if that is possible.

Is there someone out there who got any thoughts on this? Grateful for any help I could get!

Sorry for making this post so long. I tried my best to explain this in my limited English.

Thanks!

RBDs_from_particleEmitter_v002.hip

CLOTH_from_ParticleEmitter_v001.hip

[sadhu]

I think this link will help you

[lalleba]

Thanks Sadhu! I checked it out and managed to figure out how to spawn multiple cloth objects with one geo.

This is the results of the first test simulations. It's pretty fast, took about 1-2 min to cook the simulation.

With some tweaking I think this will be great for my purposes

By the way, is there any way to create a random seed value that can be used to create differences between multiple cloth simulations with the same setup? Can't seem to find one in the default settings.

My next step will be to try figuring out if it is possible to apply different textures to the different sheets.

Thanks a bunch!

paper_clothCopy_v003.hip