[MISC] Collision generation in NifSkope

[BrettM]

I was so happy when I discovered that one could generate useable collision for simple objects right in NifSkope. No more problems after scaling vertices and moving stuff around -- just put an appropriate-sized box around the modified mesh and make a convex collision out of it. Not fancy or optimized, but good enough for static stuff.

 

However, when dealing with smaller objects, I keep getting a hull with zero vertices, which does not make the CK or the game engine very happy.  Normally I use 0.1 rounding and it works fine. With the small stuff, I've tried all kinds of different larger and smaller values, but I still keep getting that useless collision. My only option then is to find some existing object about the right size and steal the collision from it.

 

Is this a problem with NifSkope or a problem with my settings?

[Hanaisse]

It's a problem with Skyrim. You cannot use the Nifskope generated collision, it's not the right kind.

 

NifUtils is the current tool to create collision for statics. Not quite up to par for non-statics yet but still being developed. "Stealing" collision from an existing source is really all you can do.

[BrettM]

Thanks for the link, I'll take a look. The collision I've been getting, though, sure seems to look okay in the CK when I hit the F4 key. (As long as I don't get one of those zero-vertices hulls. ) I had no idea it was not kosher for Skyrim.

[Pheo3309]

I have similar issues sometimes. Only it's through using copied collisions. o.O Ended up having to generate them for the game to even recognize my containers. Any clue on what's up with that?  

[BrettM]

No, but I'd rather generate collision than steal it, because it takes forever sometimes to go through all the meshes out there to find one that's a suitable match for whatever bizarre thing I've made NifSkope do instead of learning how to model to get what I want the right way. I can't say as I've ever had any problem with a stolen collision, as long as it's hooked into my nif with all the pointers pointing to the right things.

 

With some private coaching, I did learn of three different ways to solve my problem, two of them using NifSkope. It turns out I was making a basic mistake on small objects by reducing the scaling to match the smaller rounding value. Continuing to use 0.1 for the scaling but using a rounding value of 0.02, I got a proper hull with 17 vertices for my 50% reduction of the tall, thin jar.

 

Still, I'm looking into NifUtils, since that seems to be the proper tool of choice, and I do so want to grow up to be a proper modder someday.

[Pheo3309]

I made mine a little bigger being that the whole mesh for the jars I just released, was wider than the collision generated. I may shorten them in future versions, but bleh. Collisions are contankerous sometimes. I had mine plugged in from a different mesh (the same meshes I mashed up) and they weren't reacting in game. =/ 

 

But they work! So I'm not complaining now. I'm just wondering why things went wonky. I could have been doing something wrong though. With battling chest congestion, I was pretty heavily sedated with NyQuil. I guess modding isn't advised when sick and groggy. 

[Vain]

What about removing collision... is that also done using the NifUltils.  For example a doorway has collision blocking it but you want to be able to move through it.

The sucess of walking into my house through a giant dragon skull depends on this!

[Hanaisse]

You would have to completely remake a new collision for it.

[Vain]

I'm okay with that.  I have no idea how.  I need something other than the Creation Kit... but what?  My toolbox only has one tool in it and I need to know what other ones I need.

The tool to remove the unwanted collision.

and

The tool to import the now desirable object into the CK.

 

Possibly more, but I have no idea which is why I'm asking.

[BrettM]

You can completely remove collision with NifSkope. Just delete the bhkCollisionObject branch. Poof. It's gone.

 

But I don't think you want a doorway completely without collision. You would need to make something that fit the mesh without blocking the opening. While you can actually make a new collision for a static object using nothing but NifSkope, it's a very primitive collision and would just cover over the opening you want again.

 

Making a new one that will really work for you is going to require the ChunkMerge part of NifUtils and something else, like Blender, to make a shape that tells ChunkMerge how the collision should be laid out. I haven't learned how to do that kind of collision yet, but there is a tutorial by Insanity showing the basics. See "From Blender to Skyrim" for details.