Topic: Yet another Collision problem.....HELP (Read 1457 times)

chebob69 · « **on:** April 27, 2010, 04:35:19 PM »

For saying rad is so good with basic physics, it seems to have a lot of problems with collisions of various kinds.

Has anyone else had this problem?

I have a house skinmesh with a low-poly rigidbody attached to it. This is aligned with the default rigidbody platform and I'm navigating with a fps cam. Every now and then while I'm walking against the edge of the house, the fpscam will slip through the edge of the rigidbody or through the floor. This has only ever happened when the fpscam is colliding with 2 separate rigidbodies independently of each other (i.e the house is not interacting with the ground). The same problem is happening with custom made terrain but NOT with the default terrain.

Yes the rigidbodies are closed hulls
and
No the fpscam is not moving too fast (standard walking speed)

HELPPPPPPPP

genetransfer · « **Reply #1 on:** April 27, 2010, 05:08:18 PM »

does your house rigid body have a floor? if so remove that. if it's just the walls sink them into the terrain abit. failing that it could be the resolution of the collision body or the model itself. but I haven't had these problems in years so somone else might have the solution if what I said doesn't help.

chebob69 · « **Reply #2 on:** April 27, 2010, 06:27:35 PM »

It's definitely not the models, they're all very basic.

What do you mean by floor? It is effectively a closed cube so it has a base. You're saying I should delete that? Leaving an open mesh?

n_iron · « **Reply #3 on:** April 27, 2010, 06:29:09 PM »

Hi chebob69
If the 3d model has double sided pollies and you make a rigidBody out of it the collision detection can allow the colliding object to go straight through and 3drad may even crash.

When you build your rigidBody make sure the walls are thick and there is no chance of the collision being detected by the other side of the wall. I found this out some time back. This also applies to floors and ceilings.

This is some thing Sketchup users must also be aware of.

n_iron

chebob69 · « **Reply #4 on:** April 27, 2010, 06:39:07 PM »

It's not made out of double-sided polys.

As I said, it's effectively a closed cube so no thin sections or anything.

genetransfer · « **Reply #5 on:** April 27, 2010, 06:50:26 PM »

Quote from: chebob69 on April 27, 2010, 06:27:35 PM

It's definitely not the models, they're all very basic.

What do you mean by floor? It is effectively a closed cube so it has a base. You're saying I should delete that? Leaving an open mesh?

i was thinking of a detailed house collision model that you could go inside of hence removeing the flor inside and just useing the terrain for the ground was what I meant.
but a simple cube just sink it into the terrain and see if it still happens or adjust the collision resolution to be smaller.

Weapon121 · « **Reply #6 on:** April 27, 2010, 06:52:43 PM »

Ive had this happen to me with perfectly modeled rigidbodies. You have to find a "Balance" between both rigidbodies, by adjusting the resolution on one of them or both, so that the colliding sphere based rigid doesnt fail when touching both at once. For me it was a trial and error solution. Eventually, I got them to "get along". another solution is to "merge" both rigid bodies in your modeler and load it into Rad as one Rigid instead of two different ones.

n_iron · « **Reply #7 on:** April 27, 2010, 07:57:24 PM »

Weapon121 is right check the resolution first.

Ok now it looks like we have a continuing problem that only applies to you.

Is there any way to check if the vertices are welded in your modeling program. If they are not this will also cause the problem.

n_iron

chebob69 · « **Reply #8 on:** April 27, 2010, 07:59:52 PM »

I promise you, the mesh is completely closed. It'll be the resolution, I'd never really altered it. That would certainly make sense. I'll assume the collision resolution fernando used for the default terrains is different than a custom rigidbody, that would explain it.

If you read this, could you advise me on this values Fernando?

n_iron · « **Reply #9 on:** April 27, 2010, 08:34:24 PM »

I have never changed the resolution on any models I have created or bought. You may only ever need to change this if you made a rigidBody with extra large pollies.

I not talking about closed hull (which is not totally necessary) I am talking about if vertices are welded or not this can make a difference.

n_iron

chebob69 · « **Reply #10 on:** April 27, 2010, 08:45:52 PM »

Surely a closed hull implies all the vertices are properly welded?

n_iron · « **Reply #11 on:** April 27, 2010, 09:02:02 PM »

No what I am talking about is a model may look all right but the vertices are not all connected. A polygon has 3 vertices and each vertice should be joined by another vertice some times the vertices look joined but are not. The models (.x file) information on vertices may get messed up during modeling or maybe when exported I not sure. I think what happens in the x file is you end up with 2 or more sets of data for the one vertice. Some modelers have weld vertices option to fix this but beware of using it.

n_iron

chebob69 · « **Reply #12 on:** April 27, 2010, 09:40:22 PM »

Ok I think we're on different pages. I know how to weld vertices. That's not what the problem is.
I was pointing out that a closed hull implies all of the correct vertices are welded (that's pretty much the definition!)

n_iron · « **Reply #13 on:** April 27, 2010, 10:28:31 PM »

Sorry I have run out of ideas maybe some else may shed some light on the problem.

Quote

Yet another Collision problem.....HELP

I say this has been a re-occurring problem for you so you must look closely at what may cause it. I also had a problem like this some time back and found it was my modeler program which I eventually up graded.

n_iron

chebob69 · « **Reply #14 on:** April 27, 2010, 10:42:56 PM »

I use 3ds max, no upgrading needed! It'll be the collision resolution I guess!

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Author Topic: Yet another Collision problem.....HELP (Read 1457 times)

chebob69

genetransfer

chebob69

n_iron

chebob69

genetransfer

Weapon121

n_iron

chebob69

n_iron

chebob69

n_iron

chebob69

n_iron

chebob69