Crowd Simultation: Translate/Rotate

[J_R_Boddie]

I am new to Houdini.  My goal is to create a scene with multiple formations of marching soldiers.  There will be no opportunities for collisions, so that will not be an issue.  I have an fbx model with animation.  I can create an agent, a single crowdsource (in formation) and simulation.  That works.

My question concerns translating and rotating the individual formations in the scene.  The action takes place away from the origin.  Should I translate the agent there first, then create the crowdsource and simulation or create the crowdsouce(s) at the origin and translate them to the desired location or translate the simulation node?  My experiments have produced some results that I don't understand so before blindly hacking out something that sort of works, I would like to know how an experienced user would approach the problem.

[Atom]

Overall you probably want to keep your agent animations near world origin then just populate them to a grid and they will snap to the vertices of the grid. Then managing starting formation is just creating point patterns on the grid. Also you can then translate the populating grid to where ever you want the agents to start from.

Edited March 11, 2017 by Atom

[J_R_Boddie]

If I understand correctly, you are suggesting to use the Copy SOP to apply the agents to a grid.  Then translate and rotate the grid.  That works but I have been looking at the crowdsim tools like Populate which will gives some randomization options like clip offsets.

[Matt_K]

Hi James,
Create either grids or points where you need your army to begin and feed those points into a crowdsource SOP. You can add orientation, velocity and other attributes to the points to help direct the simulation. The crowdsource node will give you options for randomisation, agent states and more as well.

Then you can use curves to constrain your army to follow a path (I usually create the paths and ray them onto the terrain) - the help has a nice army setup that's a good starting point. It's also worth watching the short tutorial on using heightfields for crowd terrains (on SideFX.com) as it can help speed up the sim too.

Hope that helps!
Matt.

 

Edited March 11, 2017 by Matt_K
typo

[J_R_Boddie]

Matt and Atom.  Thanks for the pointers.  I will look for the examples and tutorials.

[Atom]

No, don't use the Copy sop. Just use the Populate shelf tool and pick the grid.

[J_R_Boddie]

Atom.  Thanks.  That works.