Why are the ammo boxes in .bsp?

[Nash]

I notice that the ammo boxes and stuff are in .bsp instead of the usual .mdl model format like the other stuff in game. Why is that? Was there some kind of technical limitation that required them to be that way when Quake came out?

It just doesn't make sense to me. :/

[Preach]

I think there are two parts to it. One was that they needed to be boxes, as a box is very low polygon, freeing up polygons for the monsters and other important things.

This leads them to rely on the texture to make them look good. The problem was that the only skinning technique that was possible with the tools and the q1 model format was a two-sided planar map. If you just did that on a model the textures would look stretched and distorted on some or all sides. Bsp models on the other hand are very easy to align textures on, so they worked well for a simple geometric shape like a box.

Now we have better tools for models, so there are ways of making properly unwrapped models in mdl format(with a few compromises). I've made a model called pickup.mdl for quoth2 which combines all the ammo and health pickups into a single alias format model. It's not 100% identical to the bsp models - for example half a pixel on each edge of each face is cut off because of the way quake rounds skin vertices. But it's easily close enough to pass for the originals, and gets lit according to how it's placed.

[leileilol]

collision, and the fact they can glow in the dark this way

The armor was going to be a bsp box too, but this was cut

[Sajt]

Also the bsp models get semi-perspective-correct texturing in software engines, so they don't look nasty up close or when they're half clipped off the edge of the screen.

Dunno why they *really* did it though... it's pretty crazy how you can use bsp models as models...

[Chris]

The main purpose was being able to clip against bsp hulls for more precise collision.

[Sajt]

What collision? They just use bboxes (with weird off-centre mins and maxs)...

Another thing about mdls in software engines is that they are drawn with some pretty sketchy rounding, and something sitting on the floor will often seem to wiggle around when you move your view. So something non-organic looking like a big box, would look a lot more solid as a bsp model..

I think the bsp ammo boxes turned out a lot snappier than they would have looked as mdls, even if they were pre-lit.

[Chris]

In some of Carmack's dev diaries he compares the Quake1 bsp models versus the same in Quake2 tech. How previously it was preferred to use the bsp bmodel inside of a map for weirdly sized objects. One of the downsides was the lighting was always off he later explains. In Quake2 it no longer uses bsp hull clipping for bmodels like this, but you can still assign a bbox to those items, instead its only used for things like doors, elevators, etc.

also, they use SOLID_TRIGGER, not SOLID_BBOX Sajt.

There were only a few possible hulls in q1bsp, I assume akward shaped objects like the short but fat medkit or the rocket pickups were best using a bsp for it's unique collision properties rather than the few existing ones made for the player, grenades, shambler, dog etc?

I'm not entirely sure the relevance of it, but this is from his own personal accounts of it.

[frag.machine]

IMHO there is another important factor: Quake was a rushed-thru-the-door game. Surely it was easier to just slap some textures to single polygons and call them "medikits" or "rocket boxes". Remember, Quake's game design and artwork is completely incoherent at best.

[scar3crow]

Remember, Quake's game design and artwork is completely incoherent at best.

As a sum of its parts, eh maybe. But if you look at the progression of weapons, monsters, they are solid. The artwork as well is really quite good, just representing different agendas and goals. Never mind that much of the level design is downright brilliance when it comes to flow, player purpose and escalating challenge and creativity. Something most games do not even think about.

Off topic, but yeah.

I always figured the pickups were bsp rather than models because they didn't want to make a small box of shells a single point, a large box of nails the size of a player, and a box of rockets the size of a shambler... Yay limited hulls.

[Urre]

scar3: that's not related, really, since entitiy collisions can be any size already. Because of the FL_ITEM flag they're already much larger for clients attempting to pick them up, afaik pretty much shambler hull size. And like Chris said, they're not even using their bsp size, but rather a qc specified size

[jim]

Maybe this changes the subject a bit, but I've been wondering about what are these hull sizes?

[Dr. Shadowborg]

Maybe this changes the subject a bit, but I've been wondering about what are these hull sizes?

From DEFS.QC

VEC_ORIGIN = '0 0 0'
VEC_HULL_MIN = '-16 -16 -24'
VEC_HULL_MAX = '16 16 32'
VEC_HULL2_MIN = '-32 -32 -24'
VEC_HULL2_MAX = '32 32 64'

In engines and maps that do not support custom hull sizes, these values are the sizes allowed to collide with the world. (i.e. point size, player size, shambler size)

You can set the size via setsize to whatever you want, but unless your engine and map used supports custom hull sizes collisions against the world (walls, etc) will always be bound to these three sizes. Entity to entity collisions however will adhere to whatever your setsize was.

[daemon]

Another thing about mdls in software engines is that they are drawn with some pretty sketchy rounding, and something sitting on the floor will often seem to wiggle around when you move your view. So something non-organic looking like a big box, would look a lot more solid as a bsp model..

I think the bsp ammo boxes turned out a lot snappier than they would have looked as mdls, even if they were pre-lit.

I think this is the exact reason.

[Urre]

As far as I understand it, that only happens when mdl's animate. Tomaz made a pack which replaced the bsp ammoboxes with mdl equivalents, and they looked generally a lot better thanks to lighting stuff. Don't recall any vertex swimming

[FrikaC]

IMHO there is another important factor: Quake was a rushed-thru-the-door game. Surely it was easier to just slap some textures to single polygons and call them "medikits" or "rocket boxes". Remember, Quake's game design and artwork is completely incoherent at best.

Says you.