Sketchup

[FernandaCassia]

I'm trying to create a house in SketchUp. Whenever I upload it to the second life it seems to have an invisible prim that causes the avatar to be above it, I activated Phantom in it and then my avatar was below it, I thought to put a prim, but whenever I put the prim with the house the Phantom is active in both and my avatar re-enters the same, how to solve this?

 

[Aquila Kytori]

4 hours ago, FernandaCassia said:

I'm trying to create a house in SketchUp. Whenever I upload it to the second life it seems to have an invisible prim that causes the avatar to be above it, I activated Phantom in it and then my avatar was below it, I thought to put a prim, but whenever I put the prim with the house the Phantom is active in both and my avatar re-enters the same, how to solve this?

 

 

 

The reason is that your model is set to Physics Shape Type : Convex Hull. Think of Convex Hull as if your model has been wrapped in cling film. You need to set the Physics shape type to Prim. (You will find this option in the Features tab of the SL build floater)

To have access to this Prim option you need to have chosen a collision model in the Physics tab of the mesh uploader at the time you uploaded the original visual model.

To have accurate physics/collisions surfaces for your avatar to interact with (and low physics costs) its almost always best to create your own Physics model. Its important to keep this physics model as simple as possible. Only add collision surfaces where you really need them. Avoid small or long thing faces in your physics model because these can increase the physics cost (final LI cost) dramatically !!!

The overall X Y and Z dimensions of the physics model should be the same as those of the visual model. (If different then the collision surfaces will be offset).

Below is a screenshot of what a Physics model for your building should look like :

Save this Physics model as a separate .dae file.

You will now have 2 models to use in the mesh Uploader, 

1: your original Visual.dae model.

2: this new Physics.dae model.

In the mesh uploader, load up your visual model as usual then open up the Physics tab and load up your Physics.dae file.

 

Hit the calculate weights and fees button then the Upload button.

 

When you have your building rezzed  in world,  edit it and in the Build Floater open the Features tab. Its here that you will find the Physics Shape type menu. By default it is set to Convex Hull (cling film wrap). Choose the Prim option. Now you should be able to walk around inside your building and have accurate collision surfaces.

I don't use Sketchup so..............                  but the above is how it would be done in Blender.        Hope this works for you

Edited April 20, 2019 by Aquila Kytori

[Wulfie Reanimator]

9 hours ago, Aquila Kytori said:

Below is a screenshot of what a Physics model for your building should look like :

I think your image needs a couple asterisks.

While you might want to avoid "long and thin" shapes (a regular wall is not thin enough to be a problem), you should also avoid small gaps (two normals facing each other), because small gaps seem to cause huge LI penalties when you scale down the object. (Gap gets smaller = more physics accuracy needed = LI goes up.)

And when you don't close the end of your wall, the avatar can walk into it, like the pieces of wall on both sides of the slope. Leaving the top of the wall might be okay, but definitely not the side that's facing the walkable area.

Edited April 20, 2019 by Wulfie Reanimator

[Chic Aeon]

Great to see Aquila posting those pretty explanations. 

The bottom line which no one is saying out loud but that you can find on Oh SO MANY threads here is that Sketchup is NOT a good program for SL.   Aside from the physics issues there are other problems. So you (the OP) might want to do some research here on the forums before you commit hardily to Sketchup :D.   

Good luck with your building adventures and enjoy the journey!

 

 

[Aquila Kytori]

21 hours ago, Wulfie Reanimator said:

I think your image needs a couple asterisks.

While you might want to avoid "long and thin" shapes (a regular wall is not thin enough to be a problem), you should also avoid small gaps (two normals facing each other), because small gaps seem to cause huge LI penalties when you scale down the object. (Gap gets smaller = more physics accuracy needed = LI goes up.)

And when you don't close the end of your wall, the avatar can walk into it, like the pieces of wall on both sides of the slope. Leaving the top of the wall might be okay, but definitely not the side that's facing the walkable area.

Thanks Wulfie

To late to edit my original post so have to add the  screenshot here instead. I understand what you mean about the wall ends at the sides of the stairs slope so that's one asterisks but for the second,  I'm not seeing the "avoid small gaps (two normals facing each other)," that you mentioned?

 

 

 

[Ulfilas Graves]

Old tutorial, still relevant and includes Physics info

 

Edited April 12, 2020 by Ulfilas Graves

[Kyrah Abattoir]

Depending of the wall thickness, your collision mesh might not even need to have two "sides" per wall.