Physics problems

[Fox Nacht]

Hi there,

I'm losing my mind trying to upload a barn I created in Maya 2015.

I've tried everything I could think of.

Made a physics shape using Planes. No dice. The uploader mangles it such that it looks nothing like the actual .dae.

Tried with a box shape - super simple- looks like this:

http://gyazo.com/062923a19d7094ee09499cf9281b883c

But the uploader mangles that as well:

http://gyazo.com/27e6d34ec4f3b2d923630f1900af45bf

I'm at  acomplete loss as to what it is I'm doing wrong.

I've followed the advice on a few threads here, but to no avail.

Any help would be greatly appreciated.

Cheers!

 

 

[Fox Nacht]

More details:

here's what happens if I upload a version without doors, and with the box physics shape

http://gyazo.com/9cc54b96fd935ba5bbf1a00e106dc60b

this is what teh shape looks like again:

http://gyazo.com/062923a19d7094ee09499cf9281b883c

If I try the exact same mesh (without doors) and ask it to do it's own physics I get an error:

"Failed to upload:Multiple errors while validating asset."

But it lets me do it without physics... Halp!

[Fox Nacht]

ok.. answering my own questions..

I guessing my main issue is that I didn't realize that each object in my mesh needs a corresponding physics object.

Massive issue as it's all separate objects which need to remain that way due to textures (all UVs mapped and I simply don't have the time on my deadline to re-do them all).

SO: new question. Is there a way for me to upload the multiple object barn, without doors, and have the uploader create physics that include a hole where the door is? If so, how do I do it?

[Drongle McMahon]

Not really enough info to tell, but my guess is that your main model and physics shapes are both made up of sevearal separate mesh objects. It's best if they are each a single mesh. However, not knowing what software you are using, I don't know if you can arrange that.

Anyway, there are a couple of important things: First, when the uploader has a mesh object assocuated with a visible mesh object, it will stretch and/or squash the physics mesh to fit the bounding box of the high-LOD version of the visible mesh object. So even if your meshes were single objects, the physics mesh would get stretched to the full height of the roof, blocking sideways access to the roof sapce and raising the floor level. You neeed to make the physics mesh so that it fits without stretching or squashing.

Secondly, if you visible model is composed of multiple mesh objects, then when it comes to the physics model, it will associate one mesh object from the ohysics model with each objevt in the visible model (applying the stretching as above in each case). It takes the mesh objects in the order they appear in the collada file. So you have to make sure the physics pieces each match the size of the visible pieces, and that they are in the same order in the visible model and the physics model files. (Simple, isn't it :matte-motes-smile:). You can arrange the order in Blender by naming appropriately and selecting alphabetical ordering. I don't know how to do it in other software. Anyway, the complications of using multiple objects is one of the reasons it's better to join the obnects.

You can also use an alteranative approach, which is to upload visible and physics models separately, then link them inworld with the physics model as the root and, setting the visible model to physics shape type "None", and giving the physics mesh 100% transparent (e.g. use "Default transparent" texture from the library). In fact, you can achieve the same thing by using ordinary prims for the physics shape. As long as you stick to boxes that not distorted in any way other than stretching, cylinder only stretched along their axis, and perfect spheres, this kind of physics has low physics weights and should not inflate your Land Impact much.

[Drongle McMahon]

"Is there a way for me to upload the multiple object barn, without doors, and have the uploader create physics that include a hole where the door is? If so, how do I do it?"

Depends a lot on how it was constructed. You could try using the high LOD meshes as the physics model and decomposing (ie clicking "Analyze"), or maybe even not decomposing. Either way, and especially if you don't "Analyze", the physics weight might push up the LI unacceptably. If you use the "Simplify" options, after decomposing, you may be able to reduce it, but you are also likely to close up any holes there are in any single mesh object. It's also possible you might get away with using the lower LODs, You'd have to look at them in the previewer to see whether they might work.

None of that is really recommended. It's always better to use a purpose-built physics shape if you can.

You can put up to eight different textures on a single mesh by using materials. It doesn't matter if the UV mapping for the faces with different materials overlap, because the are used separately for each texture and don't interfere with each other. In fact it's better if they do overlap, as otherwise you are wasting UV space for each texture.