Blender-collision model

[Kaos Jansma]

I made an object in Blender, uploaded it to sl, and parts of it are not solid - certain parts are ok, other parts my legs sink down to the knees, and other parts, i fall right thru it.

How can i add a collision object to my original object in Blender 2.5?

i have searched and still am not clear  of the process.

Thank you for any help or guidance!

 

[hibit Spad]

There is a couple of ways to manipulate the physical/collision layer.

first try to do an upload,  in the upload window you should see a tab labeled physical.  Once you are there you will have the option of useing one of your LOD layers or imported a seperate file that will become you physical layer.

 

If your model has holes in it that you want to walk through (like the walls of a house),  it is usually better to make your own physical layer.

 

Something else to think about is when you make your own physical  it is going to be invisible.  So don't worry about all those fancy curves.  I have a model where I replaced a round post with a square on teh physical.  ALOT fewer vertices and no one is going to realize the difference.

[Dilbert Dilweg]

If you notice on the upload, the physics tab on step 1 there are choices for Level of detail. If you click that drop down and chose "from file", you can use that to upload a seperate collision object the shape you want.

You can find a good detailed page about the modifiers here

http://wiki.secondlife.com/wiki/Mesh/Upload_Model_UI_reference

You may find this post a good read also

Some residents did some detailed explanations

http://community.secondlife.com/t5/Mesh/Understanding-Physics-with-Builds/td-p/1464037

[Kaos Jansma]

when i upload the original Blender mesh object, the physics tab options are greyed out

I also get a VERY small object in both preview windows - not big enough to see at all

thank you both for your help - i am reviewing the information and will try again

[Drongle McMahon]

Perhaps you could tell us which viewer you are using, and some more about the model. Also, what physics shape type is it set to (on the Edit dialog features tab). If it's Convex Hull, it should be impossible to penetrate it's surface (by the definition of convex hulls), although there is a bug that shrinks the hull noticeably away from the edges of very large meshes. On the other hand, you would expect the walkable surface to be flat across the top of any depressions in the surface. If its physics shape type is Prim, then a physics shape made from the lower LOD meshes might well have a less accurately defined surface where you would expect both floating and sinjing effects.

If this is (I am wildly guessing) a landscape-like mesh that you want to walk on, and the triangles are large enough, your best bet is to make a triangle-based physics shape from the high-LOD visual mesh. This should give an accurate match between the visible and physical surfaces which you can walk on properly. To make a triangle-based shape, you specify the mesh, but do not click the Analyse button, If the triangles are too small and/or too numerous, the physics weight of the shape made this way might be prohibitively high.

I am assuming it is a mesh and not a sculpty. The physics shape of a sculpty is fixed, a bit like a sphere with flattened ends. Its size depends only on the bounding box and does not represent the visible shape at all.

[Kaos Jansma]

***Phoenix Viewer 1.6.1

***Blender 2.62

***Deck of Aircraft Carrier is the surface (yes meant to walk on)

The physics shape type is it set to ***Convex Hull & it is a mesh

***Yes it is a large mesh and the unsolid portions are near the edges

Thank you again everyone for your time and help!

[Drongle McMahon]

***Phoenix Viewer 1.6.1

- ok. I don't know about the physics shapes in Phoenix. The LL viewer uses a proprietary library for the decomposition ("Analyze"). I believe the TPVs use an open sopurce alternative which is unlikely to behave exactly the same. Maybe the viewer you are using was before this was put in? Do you have aan "Analyze" button? If not, you can't make decomposed shapes.

***Blender 2.62

***DECK OF AIRCRAFT CARRIER, SEPARATED INTO 3 SECTIONS FOR IMPORT TO SL TO COMPLY WITH THE MAX SIZE OF 64x64x64 FOR A MESH OBJECT - (THE 3 PARTS TOGETHER WILL BE 192m IN LENGTH)

The physics shape type is it set to ***CONVEX HULL AND IT IS A MESH

- In that case, you would expect to be able to walk on the surface as long as it isn't concave - which some aircraft carriers are when they have a takeoff ramp. When the physics shape type is Convex Hull, it doesn't use the mesh you have specified as physics shape on upload. It uses the default convex hull that is made whether you specify a shape mesh or not. To use the specified shape you have to select physics shape type Prim, for both triangle-based and decomposed shapes.

***YES IT IS A VERY LARGE MESH AND THE "UNSOLID" PORTIONS ARE NEAR THE EDGES

- So it's probably the convex hull size bug. In my experiments, with a 64x64 mesh, the physics shape ended 1.7m before the proper edge. I don't know whether this is a viewer (uploader) or server (physics engine) bug, so it may or may not be exactly the same with Phoenix.

- Since you have a large flat deck, you will almost certianly be better off with a triangle-based shape. Make a suitable mesh - it should fill the same bounding box as the model, but be as simple as possible (if it doesn't fill the bb it gets stretched until it does) - but don't press "Analyse". Then set the physics shape type to "Prim". You cam sometimes fall through a single plane triangle shape, so it might be worth having a double skin.

Thank you again everyone for your time and help!

[Kaos Jansma]

I do believe the bug may be the culprit and i appreciate you telling me of your own experiences.

Also am going to follow your suggestions for making the simple mesh and your guidelines for how to upload it.

Thank you for taking the time to help me with my problem and  helping me understand it  - i really appreciate it.

 

[Kaos Jansma]

SUCCESS!!!

thank you again for your time and help and especially patience

[Drongle McMahon]

:matte-motes-smile:

[Pamela Galli]

I am having the same problem with my swimming pool -- I checked it out and the physics seemed fine but then I discovered that there were in fact hole in my physics model, so part of the decking I would fall throuh, and I could get stuck in the pool walls.

 

I tried uploading physics shapes separately, uploading then with the mesh, as well as letting the uploader generate one based on High LoD.  I tried Analyze and not Analyze. I tried uploading the mesh as one, two, or more pieces.I finally ended up patching with regular prims, but since this is a curved pool, that didn't work very well either. There are still phantom spots.  I have worked on this for hours and thought I had fixed it but what I am seeing is that sometimes the pool is solid and something I fall through.

 

I am feeling a bit desperate because I released this house Saturday so need to send out a fixed pool.  I realize I may have to scrap it and make it a rectangular pool.

 

Here is a pic:  

[Pamela Galli]

Thanks to Aquila, who kindly looked at a Blender file of the pool and surround and observed that the physics shape I was trying to use was too complex, I made a much simpler one and voila!  It worked. :-)