Wondering about a mesh...

[Jokerine]

Hey all. I have a little question. A weird issue I've had with meshes in Blender is that in-game they don't havok correctly - instead, they just sort of float away and don't stop moving until I put them in my inventory. Grabbing them doesn't stop them.

 

It's an odd issue but when this happens I usually just replace the mesh with another and move on. But I got this issue again and figured I could save the mesh and share it here (as I won't be using it anyway) and maybe someone could give me an idea of why this happens.

 

The mesh is here. As you'll see, it's just a little box.

 

Is it because it's too small, maybe? Is there a limit for that? I really have no idea. Again, just wondering.

 

Thanks for any input! :)

[prensa]

Jokerine - Hello!

"A weird issue I've had with meshes in Blender is that in-game they don't havok correctly - instead, they just sort of float away and don't stop moving until I put them in my inventory. Grabbing them doesn't stop them."

This is caused by incorrect, or no settings in the object's Inertia Matrix.

The Inertia Matrix tells Havok how the mass is distributed around the object so it can be taken into account when it's interacted with.

It works along with the dimensions of the object's collision & it's Mass setting.

Problems can occur if you take a vanilla object & radically change it's size & shape, the Inertia Matrix can be off as it's set for the old shape.

Or if you create collision from scratch, the Inertia Matrix will be at a default of 0 thus the object has no inertia & will float as you describe.

You can find the Inertia Matrix by opening the object in Nifskope, expand bhkCollision, left click on bhkRigidBody & in Block Details look for "Inertia".

Expanding Inertia & you will see many slots marked m11 to m34, this is the Inertia Matrix.

Only three slots are needed to be set: m11, m22 & m33.

You can set them by double left clicking the number to the right (or 0.000 if it's new).

Before I could use Blender I would set these by finding a moveable clutter item of similar shape & size & copying the settings it used.

You can then test in game to see if the object is falling correctly to how you want it to behave.
Adjusting mass will also have an affect on the "weight" of it's fall.

Now that I can use Blender however there's an easier way to set the Inertia Matrix, just Import the object into Blender & then Export.

Blender will have auto calculated the Inertia for you.

In the case of your floaty box it gives:

m11 0.1254

m22 0.5577

m33 0.6562

You can either use the exported model or, in cases where Blender export would change too many other settings, copy the bhkRigidBody from the Blender export & Paste Over the old bhkRigidBody.

Testing in game shows that with those settings the object is no longer floaty.

By the way, your floaty.nif's BSXFlags is set to 2 which is for statics. Since it's clutter you should set it to 66.

"Is it because it's too small, maybe? Is there a limit for that? I really have no idea. Again, just wondering."

You can have really small collision objects, think of the pool table balls or the harmonica etc..

Hope this helps!

Prensa

Edited March 17, 2016 by prensa

[Jokerine]

Awesome, thank you very much for the detailed description. I'll keep this in mind next time I get another floaty mesh :)

[Deleted1205226User]

Wonderful! All the info I needed just when I needed them. :)

 

Thank you both!

[prensa]

Jokerine - Hello!

"Awesome, thank you very much for the detailed description. I'll keep this in mind next time I get another floaty mesh "

You're most welcome! :)

Take care,

Prensa


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Pixelhate - Hello!

"Wonderful! All the info I needed just when I needed them."

Always glad to be of use, especially to your wonderful animated creations. :)

Take care,

Prensa