Why do some mod-added items float when dropped?

[RoNin1971]

 

I'll have to look it up. I used it for a time but had some issues. Then i found some heated discussions between the 2 'authors' and stopped using it.

 

I'll see if I can find that thread again.

Thank you. That would be quite interesting, because I went to the NIFtool or whatever the name is discord and asked for them advice regarding collision for Fallout 4 and of the devs who is still working on forks just pointed me to a certain version that can also render primitive cylinders and he wasn't having any concerns as far as I can remember.

 

I've had no luck sofar in finding the discussion. I am pretty sure it was with the same avatar for "Jon" as on AFK, but that (old) thread doesn't look like the one I'm looking for.

 

From what I recall (its been over 2 years, so not much) there was at least an issue with the .obj import as a convex hull. Which is disabled for 2.0 Dev 7.

Besides that there is/was no way to correctly set the type of collision, so creating a convex hull (with or without .obj) will only help you get a static collision, without a type set.

 

I never found a way to create anything else (but that could just be me).

 

Note that the convex hull is only a part of the collision data. The type determines the sound too for example, or if it's moveable (for animating) or a staircase etc.

& you need to set the 'physics behaviour', which is non by default. (so it all floats in the air)

 

Not sure how to set weight and stuff, but I am sure you need to do something like that. (& again I never found a way to do anything but creating a convex hull and have Elric choke on it, for some reason. I had some other issues with nif's (not related to collisions) which where possibly (likely, but not 100% sure) caused by the dev 8 version. After reading the discussion I decided it wasn't worth the trouble and stuck to the 'official' 2.0 dev 7.

 

Nowadays I just use 3DS 2013 with the havok tools plugin, which works fine, for any collision. (Getting your hands on a 10 year old version of 3DS is the trick here, sadly)

[84Cronos]

From what I recall (its been over 2 years, so not much) there was at least an issue with the .obj import as a convex hull. Which is disabled for 2.0 Dev 7.

I always thought nifskope uses some kind of algorithm to generate the convex hull on the fly if you choose to use it. I don't really see how it should import an obj, except if it uses some kind of base convex hull.obj which is then manipulated based on your object? I just load my NIF into Nifskope and apply a convex hull if necessary, there are no objs involved as far as I can tell.

 

 

Besides that there is/was no way to correctly set the type of collision, so creating a convex hull (with or without .obj) will only help you get a static collision, without a type set.

The type of collision is afaik determned by the collision layer(which you can set) the object is on as well as the parameters in the rigidbodyinfo/entity info. Those are usually being set by the export scripts in 3DSmax(e.g. the PE Static Art script) but you can set them manually in Nifskope afaik. I've done static collision as well as movable collision so far. Everything tested with precombines/SCOLs as well. Although I'm not 100% if I'm using the correct parameters in the rigidbodyinfo since another modder just gave them to me from the PE Static Art script.

 

Note that the convex hull is only a part of the collision data. The type determines the sound too for example, or if it's moveable (for animating) or a staircase etc.

& you need to set the 'physics behaviour', which is non by default. (so it all floats in the air)

I think what you're referring to is the material. That's what gives the collision its sound and determines what kind of impact animation it's supposed to play. Again you can just set the material in Nifskope, even for different parts of the mesh. I've done combined meshes with concrete, steel and glass so far. I haven't done any staircases yet but one can change the layer e.g. to "transparent" which they do for certain objects, so I would assume it just comes down to setting the right layer for a staicase.

 

Not sure how to set weight and stuff, but I am sure you need to do something like that. (& again I never found a way to do anything but creating a convex hull and have Elric choke on it, for some reason. I had some other issues with nif's (not related to collisions) which where possibly (likely, but not 100% sure) caused by the dev 8 version. After reading the discussion I decided it wasn't worth the trouble and stuck to the 'official' 2.0 dev 7.

I haven't played too much with movable collision, but it appears that you can indeed change the weight and other vaules(which are usually handled in 3DSmax by the different export scripts). Secondly, one can do afaik all sorts of primitive collisions. The only problem is that the fork I'm using can only render primitive box collision and spheres, whereas I need another Nifskope fork to do primitive cylinders. So it basically comes down to not being able to fully render all types of primitive collision with certain forks of Nifskope and not being able to do mesh collision at all. Also Elrich not being able to process the raw collision data usually means that your NIf structure isn't in order - one needs to sanitize/reorder the blocks after adding a collision object/before processing it, since Elrich requires a specific order of nodes.

 

Nowadays I just use 3DS 2013 with the havok tools plugin, which works fine, for any collision. (Getting your hands on a 10 year old version of 3DS is the trick here, sadly)

Yeah, that's obviously the best way to do it, but 99.9% of modders just don't have 3DSmax so we poor plebs have to resort to Nifskope :wink:. I'll just keep on doing collision with it since this is all I've and it's better than having no collision, although I'm not 100% sure if it's really proper collision in the end. Anyway, thank you for your reply. It's much appreciated.

[RoNin1971]

<snip>

Generating or using an .obj for the convex hull are 2 different options.

 

I liked the idea of importing an .obj to use as convex hull, since it allows you to control its shape. The generating process doesn't always get the results you want. This is especially true for objects with inner space. (holes, curves, separated mesh (1 mesh with several parts. like 2 railings on opposite sides of stairs.))

 

For anything else, it works.

 

Now I just create a bunch of primitives, boxes mostly, and join them into 1 collision. (a collection of convex hulls for each object/primitive)

 

Next to a type (Static, animated static, weapon, clutter, invisible wall, stairs helper, navmesh cut, gas trap, etc, etc.) you need to assign a "material" as well. Not to be confused with a bgsm.

 

Like Metal, metal hollow, cloth, bone, armor heavy, or a dirt-, glass-, grass-, snow-, stone- or woodstairs. (yeah... no metal)

 

I'm no expert, so I couldn't tell you their exact significance but it seems you really need to set the material to something like woodstairs and use a stairs helper amongst other things to get stairs to work properly (for NPC's). (I usually just create 'ramps' (for the collision). Saves a lot of trouble and you hardly notice any difference when they walk up/down the stairs)

Edited August 20, 2023 by RoNin1971

[DitzyDez666]

This is all extremely horrifying lol. And thanks Ronin, I thought it was some simple little thing lolz. Now I understand why most modders have such horrible physics for their dropped items, like invisible boxes are around the item and it's floating. It's probably peeps copying a lot from other items and whatnot.

I'm probably just going to use the Nifscope method. It sounds like dude who took the feature out put it back in because it works now. In quite a few Discords modders are telling me about this Nifscope method being their current method too. I like the sound of that. lol. Wish me luck tho!

[RoNin1971]

This is all extremely horrifying lol. And thanks Ronin, I thought it was some simple little thing lolz. Now I understand why most modders have such horrible physics for their dropped items, like invisible boxes are around the item and it's floating. It's probably peeps copying a lot from other items and whatnot.

 

I'm probably just going to use the Nifscope method. It sounds like dude who took the feature out put it back in because it works now. In quite a few Discords modders are telling me about this Nifscope method being their current method too. I like the sound of that. lol. Wish me luck tho!

I added a bit of confusion there, my apologies. It was (only) the option to import an .obj as convex hull which was disabled. Not the option to generate. However, the generation only works (= gets you acceptable results) on simple shapes.

 

A much used method is to copy it from something similar. Which works fine in many cases. (I did so myself for my, not so great, Santa Hat) & some of my levers.

[DitzyDez666]

O okay, so I think Ima just copy it from the base game magazine then I guess. Like I'm doing this for the Nox Armor and Urban Raider which when dropped are just magazines that then can never be picked back up or touched, just...float for all eternity lol. So this is helpful. It's the same everything as the magazine so I figure it'll work great with it.