Two sides of mesh cube turn phantom when changing from convex hull to prim

[Ciaran Laval]

I was playing around on the beta grid last night and uploaded a couple of basic meshes, basically cubes but one has the front cut out so you can walk inside it.

So all was well when I uploaded them, did the physics stuff, bounced off all sides of the mesh as I'd expect as they are walls, with the exception of the one side that has the front missing, I couldn't walk inside whilst it was set as convex hull, so I changed it to prim.

All seemed well, I could walk inside, the problem was that I could walk out of one side of it too, one side had became phantom, it was the same with the full cube when I changed it from convex hull to prim, I could walk in and out of two sides of it but the other two sides acted as I expected, I couldn't walk through those walls.

Any ideas?

[Drongle McMahon]

How did you specify the LOD meshes and the physics shape? I am guessing here ... I think the default is to use a lower LOD. If that was a default auto-LOD mesh, then it was probably missing the offending sides. You can look at the actual physics shape by using the menu Develop->Render Metadata->Physics Shapes toggle. You can see the low-LOD meshes by using Advanced->Show Degug Options: type renderVolumeLODFactor, and lower it's value to step through the LOD switches.

[Ciaran Laval]

I used the same LOD for all four settings, the new one on the beta grid lets you use the "one above" in the menus, physics shape I loaded from file using the same file I uploaded.

I'll have a play on the beta grid over the weekend and look at the developer menu info, thanks for that tip.

[hibit Spad]

Try creating your own physics shape.  Its the same principle as making your own LOD.

 

Lots of people complaining about not being able to walk into a room/house/whatever.  The auto generater is not the greatest thing in the world for LOD or physics so you might just be better off planning to make your own no matter what the project is.

[Maeve Balfour]

With your cubes, are the visible faces on the INSIDE as well as on the outside? (Not sure if this is the case from your description). In other words, are there interior faces AND exterior faces?

Reason I ask, is that physics depends on the directions the normals are facing. An example being a single faced plane with no thickness... if you have the normal for that flat plane pointing upward, you can still walk on it, even though it has no thickness.

Mayhaps your problem side in your cube has something to do with the normal directions.

I am currently working on a series of interior room prefabs - to save on triangle counts, I am only creating faces for the visible parts of each section (the interior walls, floor and ceiling etc). When viewed from outside, the sections not being viewed from a front angle are invisible (due to their normals facing inward, in the same direction as the camera), but when viewed from inside, everything appears as expected (when assembled, the prefabs' invisible walls will be hidden by adjacent rooms or exterior walls). Anyway.... I can walk about as expected INSIDE my prefabs, but due to the normal directions, I can actually walk THROUGH the walls from OUTSIDE (due to the normals facing inward). So this might explain your issue too.

EDIT: Retesting what I mentioned in the previous paragraph.... If I have an OPEN DOORWAY of one mesh facing into the outer wall of another of my prefabs, I can walk inwards through the wall. BUT (and I don't understand this), if i try walking through the outer wall of the same prefab ON ITS OWN, it doesn't work (acts like a normal wall would). Can one mesh and its physics hull somehow override the physics of another mesh hull? Mayhaps it is a matter of overriding interaction depending on the AV's location? Very curious....

As a side note - I can see potential uses for normals in this manner - one-way doorways etc. Could be quite handy in certain circumstances.

:matte-motes-smile:

[Ciaran Laval]

Interesting, I wanted double sided textures, so in Blender I duplicated my objects and then flipped the direction of the faces on the duplicated version, this way I get textures inside and out. Sounds like you're onto the cause of the issue.

[Ciaran Laval]

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hibit Spad wrote:

Try creating your own physics shape.  Its the same principle as making your own LOD.

 

Lots of people complaining about not being able to walk into a room/house/whatever.  The auto generater is not the greatest thing in the world for LOD or physics so you might just be better off planning to make your own no matter what the project is.

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Not sure what you mean, the physics shape is based on my Blender file, I'm not using auto generate but if I make a cube and delete the front face, i can only walk inside if I turn it into a prim under features, whilst it's a convex hull I can't walk inside it.