Using impact data for wheel contact friction forces

[Andy Nicholas]

Hi guys,

Does anyone have a way of iterating through impact data inside a VOP Force DOP? I've created a bunch of points in SOPs that is pulled from an ImpactAnalysis node, and I need to access it from a VOP Force DOP.

 

I've tried pulling the points into the VOP Force as a pointcloud, and I've tried using the GetAttribute node too, but they don't work with the "op:/obj/myimpactpoints" syntax. (Is it me or is that syntax pretty flaky? It's an endless source of frustration for me!)

 

What I'm trying to do is use the impact data to generate some custom frictional ground forces for a wheel. I can calculate the forces easily enough and apply them in the VOP force, as long as I can get the impact data in, but I can't get it in there.

 

Is it possible to apply forces and torques in a SOP Solver instead?

 

Suggestions welcomed! Thanks,

 

Andy

[Andy Nicholas]

Maybe I should simplify the question. Basically, I can't get the "op:" syntax to work for the VOP Force DOP. Can anyone else?

 

If you want to test it, put a "Point Count" node down inside the VOP Force DOP, plug it into a print node, and try to read the number of points from a SOP in Houdini. It won't work for me.

 

If I save geometry out, I can read it in with a file path. But no luck with the "op:" syntax. Might be a bug, but it'd be great if someone else can confirm.

 

Thanks,

A

[paxsonsa]

Hey Andy,

 

It seems to work fine for me. Have you tried using opinputpath or op:`opfullpath()`? could it be a cooking problem?

[Andy Nicholas]

Hi Andrew,

Thanks for taking a look. Much appreciated.

 

It's bizarre, I had about 10 minutes yesterday when it worked, and then it went and broke again and it's not worked since. Crazy!

 

I suspect it must be a bug so I'm going to have to see if there's another way. I'll try simplifying the setup and see at what point it breaks.

 

Thanks again. I'll post back here if I figure it out.

 

Cheers,

Andy