Mesh Open Space For Door

[Luther Weymann]

If I am uploading a dae that I have made from three prims, and it’s a wall with an open space for a door in the middle, are there settings in the mesh Upload Model that I can set that will allow the open space for the door to be walked though without the entire wall needing to be phantom? If there are settings in the Upload Model that will allow this, what are they?

[PekeNL]

Make a physics mesh, and use that to make the hole. Don't forget to set the uploaded object to prim (and not convex hull) and you'd be able to walk through!

[Luther Weymann]

56 minutes ago, PekeNL said:

Make a physics mesh, and use that to make the hole. Don't forget to set the uploaded object to prim (and not convex hull) and you'd be able to walk through!

Oh, set it to Prim. Geez, after all my attempts how did I miss that? Thank you. Problem solved.

- On the Level of Detail tab I accept the default.
- On the Physics tab for Step 1 I select High and accept the default for Step 2.
- Upload and set mesh object to Prim.
- Door can be walked through.

[Luther Weymann]

Why after I set my newly imported mesh from Convex Hull to Prim so I can walk though the wall opening for the door, without having to set the entire mesh to phantom, why after turning it to Prim does the LI count jump from 1 to 35? I am importing as in the attached texture.

[Wulfie Reanimator]

1 hour ago, Luther Weymann said:

Why after I set my newly imported mesh from Convex Hull to Prim so I can walk though the wall opening for the door, without having to set the entire mesh to phantom, why after turning it to Prim does the LI count jump from 1 to 35? I am importing as in the attached texture.

Land Impact will always be the highest cost of Download, Physics, and Server.

At the bottom of the upload window, there's a section for "Physics Cost." The line that says "Mesh" is the physics cost your model will get when you set the mode to "Prim." (It's not intuitive but that's how it is.)

The physics model should always be the bare minimum in the complexity of its shape, avoiding high triangle counts and concave surfaces is ideal. Using the highest LOD is almost never a good idea because it's rarely efficient as a physics shape. Although we can't really see your model, we can see that it has 156 triangles which is probably not what you need for a wall with a door. I'm guessing your lower LODs are auto-generated, so using those probably won't give good results.

To get a much smaller cost (easily 1 LI in this case), you should just make a separate (simplified) mesh that matches the overall shape of your wall and select that as your physics shape, or analyze your model in order to generate one. (The physics mesh does not need to be unwrapped, textured, or anything.)

Edited November 28, 2022 by Wulfie Reanimator

[arton Rotaru]

What others have said, this is what such a physics shape should look like. Note the gaps between the boxes on the blue physics mesh. It makes the job of the hull decomposition even easier.

 

While we are at it, it's also possible to get low physics costs with so called triangle based phyiscs meshes (not analyzed). But be aware, if your mesh is less than 0.5 meters in one (or more) dimension, the physics engine will switch secretly to convex hull physics even it is set to physics shape type Prim with a triangle based physics mesh. Blocking the doorway.

[Wulfie Reanimator]

8 minutes ago, arton Rotaru said:

While we are at it, it's also possible to get low physics costs with so called triangle based phyiscs meshes (not analyzed). But be aware, if your mesh is less than 0.5 meters in one (or more) dimension, the physics engine will switch secretly to convex hull physics even it is set to physics shape type Prim with a triangle based physics mesh. Blocking the doorway.

This isn't exactly true, but it's also more complicated than I can explain. 😅

The minimum size is 0.2 meters, but only for a square object. If the mesh object isn't a square, it can even be the minimum width of 0.01 meters and still keep its custom shape. There is also a certain threshold where a complex physics shape (of any size!) is forcibly turned into a convex hull.

[Luther Weymann]

Thank you Wulfie and Arton! I've now had a very big "Ohhhh! I learned more about mesh in these two replies than I've discovered on my own in the last year making little mesh objects around my house and store to cut down on my total LI. Now I have some mesh study homework when I get up tomorrow. I'll post up to let you know your kind replies produced some good results.

[arton Rotaru]

14 minutes ago, Wulfie Reanimator said:

This isn't exactly true, but it's also more complicated than I can explain. 😅

The minimum size is 0.2 meters, but only for a square object. If the mesh object isn't a square, it can even be the minimum width of 0.01 meters and still keep its custom shape. There is also a certain threshold where a complex physics shape (of any size!) is forcibly turned into a convex hull.

Unfortunately it is true. Note what I have written, "triangle based" physics meshes. Make such a doorway, don't analyze the physics, set to Prim, make it's width 0.49 meters, and be happily blocked. 😇

It's true that a <0.2, 0.2, 0.2> or less object will be convex hulled regardless of it's physics type, Hulls or Triangle based.

Edited November 28, 2022 by arton Rotaru

[Wulfie Reanimator]

13 hours ago, arton Rotaru said:

Unfortunately it is true. Note what I have written, "triangle based" physics meshes. Make such a doorway, don't analyze the physics, set to Prim, make it's width 0.49 meters, and be happily blocked. 😇

It's true that a <0.2, 0.2, 0.2> or less object will be convex hulled regardless of it's physics type, Hulls or Triangle based.

Ah, I see my mistake. This is what I tested with when I wrote my post:

My avatar is standing in the gap (mesh is 0.01m thin) just fine, but the model is already convex so that's working as you would expect. (It turns into a cube at 0.2 meters too. I'm used to seeing the shape looking like that square since that's what more complex objects get turned into.) Using an arch also worked as you said.

Edited November 29, 2022 by Wulfie Reanimator

[Luther Weymann]

Everyone seems to have some limit on their ability to solve problems. I’ve found yet another one of my limits. After a great 35-year career in the technical side of the software business which my ego got me to think I was smart, I’m unable to understand exactly what I am supposed to do to make a mesh wall with a doorway that I can walk through. I am at 41 uploaded failed attempts over the last two days, trying every possible combination and trying to understand the wonderful people on the forum trying to help me. At the end of the day, it is just a virtual world, and it’s not so important that I can’t just make the whole wall phantom and move on. We all fail at something. At least this one I can live with. Thank you for trying to help.

 

 

Edited November 29, 2022 by Luther Weymann

[arton Rotaru]

You know, 42 is the answer. Jokes aside, I get your frustration. There is a debug display in the viewer that shows the physics shapes. This way you can see whats actually going on.
Develop > Render Metadata > Physics Shapes.

 

Just in case, the Pyhsics Shape Type will be set under the Features tab of the Build floater.

[Wulfie Reanimator]

5 hours ago, Luther Weymann said:

Everyone seems to have some limit on their ability to solve problems. I’ve found yet another one of my limits. After a great 35-year career in the technical side of the software business which my ego got me to think I was smart, I’m unable to understand exactly what I am supposed to do to make a mesh wall with a doorway that I can walk through. I am at 41 uploaded failed attempts over the last two days, trying every possible combination and trying to understand the wonderful people on the forum trying to help me. At the end of the day, it is just a virtual world, and it’s not so important that I can’t just make the whole wall phantom and move on. We all fail at something. At least this one I can live with. Thank you for trying to help.

If you'd like help in-world, lemme know. Below you can see the steps I took to upload a wall like yours.