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Floating above mesh problem


Jo Yardley
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I know this has been mentioned before, but can't find an answer.

I've been making a  very very basic mesh floor with Mesh Studio.

I've used it a lot, made lots of things before.

So for this floor, I just stick a few prims together and turn them to mesh.

But when I walk on it, I float above it, sometimes a little, sometimes a lot, always more then with regular prims.

I've tried a few things, like making a custom physics model, invreasing the triangle limit, the highest LOD the viewer offers, etc.

It still happens.

What am I doing wrong?

The floor is very simple, just blocks with textures on top, bottom and side.

 

Picture 1: Here the floating is minimal, something I could live with if I had to.floor1_001.jpg

 

Picture 2: This is getting ridicilous floaty, I've build it with the same exact technique as the floor above. 
But this floor is higher up and a little thinner.floor1_003.jpg

 

Picture 3; another floor test, feeling like a ghost.

floor1_004.jpg

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I am not sure how far the capabilities of mesh studio are reaching.
I am exclusively using 3D Software for years (Blender, Max, 3Ds etc ) to create my models and wouldn't want to miss these =)

Since i don't know how exactly mesh studio converts the prims into actual mesh data i can only give some general pointers.

Some solutions could be:
- to offset the pivot point of the physics shape. (so that it is placed deeper / on a lowered Z value)
- to make the physic shape a tiny bit being a tiny bit smaller then the original meshs outter shape.
- check if the physics shape of the object is set to prim
- the physic shape should in best cases be a very simple form of your mesh's shape, try to make planes (quads / polygons) if mesh studio offers that capability
- change the thickness value
- when you import the dae files you made with mesh studio check in the uploader window of SL how the physic shape looks (is it maybe too far offset around the mesh's shape, or shows any other oddieties) - enable this preview by setting the options below the preview window to physics.

- If the physic shape made with mesh studio appears to create a problem on this object try to use the uploaders object simplification : http://wiki.secondlife.com/wiki/Mesh/Decomposing_a_mesh_for_physics_shape.

Some more helpfull links regarding mesh studio and physics in general:
http://wiki.secondlife.com/wiki/Making_Mesh_Physics

 *
https://sites.google.com/site/tamaproducts/home/mesh-studio

* With Mesh Studio, you could make everything invisible, on a copy of your linkset, and just make visible the faces that will be used for collision.  This simplifies your mesh for physics and then you can follow the information in the Cel Edman videos when you upload it with your Collada .dae file.

Cheers, Code.

 

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Thanks for the information so far, I'll be looking into a few things.

But first, here is the physics shape.

As you can see it is pretty spot on, I cant see a reason there why I'm floating.

At least, if I'm interpreting the image properly.

I would think it had to do with my avatar, if I had not tested it on normal prims and seen that there is no problem there.

floor1_005.jpg

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what does it look like in the SL mesh importer when you inspect the physics preview ?
is the physic mesh offset there maybe? (higher than the top of your box ?)

I assume this screenshots shows the prims you are using to make that physics shape. It would be good to see how this one is actually interpreted (and possibly offset, or other issues) by the uploader. Could be a hint for needing a lowered pivotpoint or different shaping etc.

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ok that sentence was prolly misunderstandable or not reaching far out enough.
To clarify : those at least -looking-like prims 'beneath the mesh' (with grid textures and rulers) are the ones you are making the phyics shape from?

I am trying to grasp the concept of how meshstudio defines / builds the mesh (and mesh you use as physics shape) - as far as i've seen when checking for you they create them still from prims (just as in their former sculptstudio). Meaning the prim is being used as refference where the vertices will be etc.

bare with me lol, i can explain you how to make models (and physic shapes) in almost every 3D software, and explain you how to implement it into various engines or platforms. Just normally ignore  those 'inworld tools' for making anything of that matter. But yet still trying  / willing to help.

And i'd still like to know what you see when you inspect this uploaded physics shape in the meshuploader window. Is there any noticeable offset or misplacement ? Or is it just as tight as it appears to be in the inworld view?

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Codewarrior Congrejo wrote:

ok that sentence was prolly misunderstandable or not reaching far out enough.

To clarify : those at least -looking-like prims 'beneath the mesh' (with grid textures and rulers) are the ones you are making the phyics shape from?

 

I am trying to grasp the concept of how meshstudio defines / builds the mesh (and mesh you use as physics shape) - as far as i've seen when checking for you they create them still from prims (just as in their former sculptstudio). Meaning the prim is being used as refference where the vertices will be etc.

Mesh Studio generates mesh from the prim surfaces.  When you import the dae file to Blender, it can be worked on as any mesh.  To keep faces from generating mesh, we use a value of 100 in the Edit Window's Transparency setting.  Thus we can create a single plane by making all faces, but one, transparent.  We can also create a single triangle by tapering the face.  To create physics meshes, we often use a box prim or a single face to describe the collision surface and this generally works as it would in any 3D program where we have created LOD meshes and a physics mesh and upload them through the SL Uploader.

 

bare with me lol, i can explain you how to make models (and physic shapes) in almost every 3D software, and explain you how to implement it into various engines or platforms. Just normally ignore  those 'inworld tools' for making anything of that matter. But yet still trying  / willing to help.

 

And i'd still like to know what you see when you inspect this uploaded physics shape in the meshuploader window. Is there any noticeable offset or misplacement ? Or is it just as tight as it appears to be in the inworld view?

 

If you would like to see a general workflow for Mesh Studio that includes a simple physics mesh as well, you can view my Mesh Studio Walkthrough in my Mesh Studio blog:  

~ele

 

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Drongle made a great explaination of what's going on in a thread I asked a couple of months ago.

http://community.secondlife.com/t5/Mesh/Walking-on-Water/m-p/1756173/highlight/true#M18106

I followed it and got a perfect floor!

 

OK. Here's the bad news. That perfect floor (yes it was) CHANGED and reverted to floating. Now the mesh of course didn't change. It was uploaded onto Agni and was great for a week or so. Then one day I noted that I was once again walking in the air. Checked to make sure my feet were actually on the ground when there WAS ground (I use Firestorm which let's you fix that easily) and that wasn't the issue.

Then I checked a few building from some very wellknown mesh creators. Ones that also had been perfect when I got the houses. They were also in the walking in air mode and have stayed that way until this day. I just ignore it.

So, since that time, I have started setting my mesh floors to "none" and putting a movable and invisible prim (can be mesh or original prim) piece in there in case the rules change again and the server decides to interpret things differently. It costs .5 LI and saves a lot of hair pulling. I have seen mention of others doing this too.

Again, Drongle's trick DID work perfectly. I just no longer have any faith in the permanence of the mesh floor physics :D.  Using a "real" prim in the floor also let's you rez things on the floor which can be a pain on a mesh floor.

 

 

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Analyzing or not analyzing in the mesh uploader makes a difference whether or not  you are using 2 simple  planes or a flattened cube shape for the  Physics shape of the floor.

In all the examples below the floor was set to Physics Shape Type Prim.

First is of the mesh floor in Blender and then my avatar standing on a normal resized cube set to Physics Shape Type Prim:

floor phys 1.png

 

Below is th mesh floor uploaded using the 2 planes for physics :

floor phys 2.png

 

and the next is the same mesh floor but using the High Lod (ie the same mesh for physics as the mesh floor itself )

floor phys 3.png

So for floors it proabaly better not to Analyze in the uploader  .

 

 

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Interesting stuff, thank you all.

Still experimenting.

I think I will have to use prims inside the mesh to solve this, mostly because I have a lot of tenants and I don't want them to call me everytime they have trouble rezzing stuff because their floor is mesh.

So that will solve 2 problems at once.

But I still want to figure out how we can solve this so I will keep trying your suggestions and a few techniques to see what happens.

But for now, the invisible prim inside a mesh floor will have to do.

 

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Oh what also works is simply putting the same mesh floor inside the mesh floor, making the top one phantom and then loverling the second one a little till you feel the physics are perfect.

The same mesh floors can be less LI then if you did this with prims.

Problem of course is that you cant neatly link everything together, but for now, it will do.

 

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