Jump to content

My uploaded mesh doesnt show the physic shape


You are about to reply to a thread that has been inactive for 2105 days.

Please take a moment to consider if this thread is worth bumping.

Recommended Posts

Ok once again , sorry for my questions , but now I was trying to add a physic shape to my model , but what I see is that it doesn't select the physic model ...

 

my mesh is made of 6 faces or parts , 4 materials , 4 lods ... but when I upload the physic shape , wich is one single block , it doesn't get uploaded and instead it selects the highest model ...

 

why?

 

do I need to make a collision model for each face? What if 4 of those are just leaves?

Link to post
Share on other sites

"my mesh is made of 6 faces or parts , 4 materials , 4 lods"

Not sure exactly what you mean here. Don't know what software you are using. ???

A mesh model in the 3D program should be model < objects(meshes) < materials* < faces(polygons)>>>

In SL, these become Linkset < prims < faces < triangles >>>

The differences in terminology can be confusing.

In the LOD and physics models, there has to be one object for each object in the high LOD (reference) model. If there aren't, the uploader will use the default (low LOD) mesh for each object where it doesn't find an object in the physics model. So if you want to control the physics shape completely, you need to have a separate mesh object for each of your high LOD objects. You can't just use one box for the whole collection.

Note also that the physics mesh for each object will be stretched/squeezed to fit the bounding box of the corresponding high LOD object, not the whole model. If you make the physics model just a collection of identical cubes, one for each high LOD object, then each will end up with a physics shape fitted to its bounding box (which sounds like good enough for what you want?).

*the same material properties may be re-used on different objects, but this doesn't affect the data structures uploaded to SL, where that common reference is lost.

Link to post
Share on other sites


Naiman Broome wrote:

Ok once again , sorry for my questions , but now I was trying to add a physic shape to my model , but what I see is that it doesn't select the physic model ...

Like Drongle, I'm not absolutely sure what you mean either but I can hazard a guess: Are you using Firestorm to upload? If so, make sure you use the 32-bit Second Life only version of the viewer. The 64 bit Firestorm can't handle physics on mesh uploads properly because the software code needed for it doesn't exist in a 64 bit version and the Firestorm version for multiple grids can't handle it because they're not allowed to include that software code in it. (This is not Linden Lab being difficult btw, the physics software is not LL's own, it's bought from Intel - or rather an Intel subsidiary - and the license only covers Seond Life only software.)

Link to post
Share on other sites

Hello I am using 3dsmax and the latest test mesh viewer from LL ...

 

as for the collision so far I tried to upload a mesh that I exported as 6 objects , ( or 4 recently ) that use one multimaterial with 4 submaterials .

this because I wanted to fine tune the 3 objects that share the same material with different coloring , but then I opted to make them all one object and so I exported as 4 in total .

 

since my modelis a tree I only need the collision for the main trunk , how I am supposed to make the collision for the other stuff? that should be passthrought?

 

Shoudl I make just as triangle? And how I tell SL engine wich collision correspond to wich object? will I have just to use the same materials on each or name them in a certain fashion?

 

Also how I do to make only some of those collideable ( actually just the trunk ) and the rest no collision at all?

 

thanks for your kind answers .

Link to post
Share on other sites

Hello I am using 3dsmax and the latest test mesh viewer from LL ...

Again, I'm not sue which viewer that is. Can you paste the top line from the box that appears when you do "Help>About SecondLife" in the viewer before you log on. I ask because there is a development viewer "Project Importer" that has some big differences in mesh upload, especially for materials and niming of LOD and physics models. If that is what you mean by "latest test mesh viewer", then there are different issues to consider. I will stick to the current release viewer for now.

as for the collision so far I tried to upload a mesh that I exported as 6 objects , ( or 4 recently ) that use one multimaterial with 4 submaterials .

this because I wanted to fine tune the 3 objects that share the same material with different coloring , but then I opted to make them all one object and so I exported as 4 in total .

 I am unfamiliar with the concept "multmaterial". In the exported collada, there are just materials. Each mesh object is allowed up to eight different materials. The parts of the mesh assigned to each material will end up as an independently textured face in SL, which can have its own texture, colour and animation. So it sounds as if you can combine the whole model into a single mesh.

since my modelis a tree I only need the collision for the main trunk , how I am supposed to make the collision for the other stuff? that should be passthrought?

 As I said elsewhere, you need a collision model for each mesh object, or the uploader will make one for you. If you keep the other parts as separate meshes, and make the trunk the root of the linkset, then you can set them to physics type "none" inworld. You can't set the physics type of the root prim to "none" and you can't set different physics shape types for different materials.

Shoudl I make just as triangle? And how I tell SL engine wich collision correspond to wich object? will I have just to use the same materials on each or name them in a certain fashion?

 Also how I do to make only some of those collideable ( actually just the trunk ) and the rest no collision at all?

 Remember that the physics shape, of each mesh object, is stretched to the size of the visible object. If you combine all into one mesh, you can use a solid box or cylinder for the trunk physics, but you will need to add at least two triangles in the top opposite corners of the bounding box to make the shape fit the whole tree, so that it isn't stretched. (pic coming). If you keep separate objects, then for the ones destined to be physics type "none", you can use a single triangle, ignoring how it's stretched because you aren't going to use it anyway. In fact, you can probably let the uploader generate them, fo the same reason. (If they are complex, that may add to the download weight. though)


 

Link to post
Share on other sites

Also , why when I attach all together in one element the thngs get more primmy ... like 12 prims impact , while if I leave separate 5 prims impact?

The LOD switch distances depend on the size of the object, and the download weight then depends on that switch distance. The download weight (usually ending up as LI) calculation takes that into account. In effect, the high LOD version is seen from larger distances when combined into one larger object, than when it's in several smaller objectv that switch much closer. So the combined object get downloaded and rendered more of ten. The LI is taking the increased resource use into account. You are getting improved appearance at longer distances and avoiding uncoordinated LOD switching as the reward.

 

Link to post
Share on other sites

Here's the promised pictures. There is more to learn, but that can wait. First, with separate objects for the trunk and foliage. The picture is from superimposed pictures of solid, wireframe and bounding box views in Blender. It shows one way of making the physics shape. The trunk is a proper shape to give the collision behaviour you want, The single triangle is the shape for the foliage. It's only purpose is to fill the bounding box. In fact, it really doesn't matter what this shape is, because once it's inworld, you are going to make sure the trunk is the root of the linkset and then set the foliage to physics shape type "none" so it is ignored by the physics engine. Keeping it simple though will help to minimize download weight, and thence LI.

treephys.jpg

You do need to make sure the objects in the physics model file get associated with the right objects in the visible mesh file. At the moment this is done simply by the ordering in the collada file. In Blender this can be controlled by using the Sort by Object name in the exporter (after giving the objects appropriate names). I don't know how to do that in other software. This is differenr in the Project Import development viewer, where (last time I looked) special naming conventions are used to match objects in LOD and physics files.

treephys2.jpg

Second, the two objects have now been cimbined into a single object, with two materials for trunk and foliage. Now that there is only one object instead of a linkset, the single prim is the root prim, and it can't be set to physics shape type "none".  So the big triangle would be a problem. It is replaced by two tiny triangles that are just enough to make sure the physics shape fills the bounding box, so that the important trunk part doesn't get distorted by stretching to fit. (There is a way of making the two little triangles invisible to the physics engine, by making sure their normals point away from the rest and using "solid" option of Analyze, but they won't be a serious problem here anyway). You will need to "Analyze" a shape like this. A triangle-based shape, that you get by not Analyzing, hates small triangles which will therefore cause high physics weights and LI.

ETA: added sentence about Project Import viewer.

 

Link to post
Share on other sites
You are about to reply to a thread that has been inactive for 2105 days.

Please take a moment to consider if this thread is worth bumping.

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
×
×
  • Create New...