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Cliffs & Caves Content Pack

Name:	Ben Acord
Date Posted:	Aug 20, 2007
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Blog post

My own game project requires detailed cliffs and caves with defined pathways. The thought occurred to me the other week that maybe, just maybe, some other designers would like to have the same thing. Especially after looking over the forums and seeing a lot of questions about caves, set/clear empty, and cliffs. Why is this needed? My primary answer to this question is to eliminate a players view of 'stretched' terrain. My secondary answer is to simply provide variety in the game scene.

Here is my proposition for a Cliffs & Caves content pack that I'll be actively modeling this week. But first eye candy of the initial 30-minute test. This is a single DTS mesh in-cropping with only 158 faces. UV mapped, painted and smoothed in Blender then exported to DTS. It has a detail texture as well.

The following is my design plan and resulting table of contents for the pack.

                            Cliff & Cave Content Pack
                            =========================
CONTENTS:
------------------

    (1) Lego-like mixing and matching of cliff pieces to form a custom face.
    (2) Low poly count and pre-defined collision geometry.
    (3) Two Types of Cliffs/Caves: 
        - Rough
        - Smooth (wind-swept desert canyon)
    (4) Two Basic Types of Caves:
        - Tunnel sections of various angles.
        - Caverns show how to blend paths, tunnels, and large open space.
    (5) Matching DTS Boulders for added variance and ambiance.
        - Standard boulders
        - Pillar boulders (stalagmite & stalactite)
    (6) Eight Base Textures per Cliff & Cave Type (item 3):
        (includes detail and bump maps for each)
        - Dark & Light Gray, Brown, Blue, Moldy/Mossy Green.
    (7) Three Ground Textures for Paths and Cave Floors.
        - Grassy Mix
        - Rich Dirt
        - Desert Sand    
    (8) All source art (models, textures)
    (9) Full-color User's Guide.
        - Assembling Custom Cliffs in a TGE Mission
        - Carving out custom Cave Entrances in a TGE Mission
        - Tunneling and Large Caverns
        - Changing a Cliff's Textures to Better Fit Your Project
        - Changing a Cave's Textures to Better Fit Your Project
        - Using Cliff & Caves Textures on the Surrounding Terrain
        - Best Practice: Optimizing Performance by Resizing Textures
        - Post-Mortem: Modeling a Large Cavern
        - Post-Mortem: Modeling a Cliff
        - Post-Mortem: Modeling a Cave

That's the plan. If all goes well I'd also like to throw in normal maps to make the low-poly models pop in TGEA. The next post will show the progress and update on the TOC.

Recent Blog Posts

List:	12/11/07 - Change Logger - Released 11/30/07 - Change Log 11/27/07 - Disaster Recovery - for the Enterprise Indie 10/20/07 - Commanding Entrance 09/30/07 - Fun with Caves 09/03/07 - Cave Update 08/25/07 - DIF Stalagmites Rock 08/24/07 - Brush Based Cliff

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Ian Roach (Aug 21, 2007 at 00:36 GMT)

im definetely interested in this :)

Kevin McLaughlin (Aug 21, 2007 at 07:10 GMT)

This DOES sound interesting.

However, you're using DTS shapes, which probably won't work from my understanding of the DIF/DTS differences. DTS models are suboptimal for landscape shapes for a variety of reasons:

- They do not take or give lighting effects. So they will not generate shadows properly or recieve lighting properly.
- AI pathing ignores DTS models. Any AIs will walk right through them. You need DIFs for AI pathing to work right.

The problems that I've read people having with caves have never been that they can't model a DTS cave/cliff; it's that modeling cliffs or ESPECIALLY caves is extremely difficult in the DIF format. And that's the format they really need to be in.

Or that's my understanding of the subject. I could be wrong here, and please correct me if I am.

J.C. Smith (Aug 21, 2007 at 09:35 GMT)

Definitely something different but have to agree with Kevin that it would work a lot better as DIFs. With Constructor you could use a DIF/DTS combination using DTS for harder to model areas, but DIF for the bulk of the geometry.

Tim Heldna (Aug 21, 2007 at 10:22 GMT)

The limitations of the DTS format for level geometry are a pain but it's not entirely out of the question. I find myself using DTS for rock like props, and I've heard that some of the "Shapes & Lines" environment packs solely use DTS.

I agree that ultimately DIF's would be better but I wouldn't completely discount DTS.

Tim Heldna (Aug 21, 2007 at 11:52 GMT)

Oh, another thing that doesn't work with DTS is decals, by default they only apply to the terrain and DIF's.

Ben Acord (Aug 21, 2007 at 12:49 GMT)

Thanks for the feedback everyone. I tossed around the DIFs for all idea but settled on DTS for cliffs after buying the Tim Aste Env Pack 1 where everything was a DTS shape. Hmmm. Deep thoughts. Would anyone cry in their root beer if it was an all DIF pack?

I'll work up several other examples and post later today (new post).

Gareth Fouche (Aug 21, 2007 at 17:08 GMT)

Don't discount DTS, it has limitations, but so does DIF. Personally I'd prefer DTS simply for the more curvy shapes. With clever collision shapes you can work around the issue.

BTW, good idea, a caves and cliffs pack would certainly have a customer here :)

Kevin Rogers (Aug 21, 2007 at 18:22 GMT)

Both have their place! With regard to cliffs and caves, IMO, use DTSs primarily for smaller objects like rocks and boulders -- things that aren't likely to occlude much geometry on their own. Use DIFs primarily for cliffs and slot canyons... To make a decent looking cave, I'd use both: DIF for the main cave geometry, and DTS for the details like stalagtites, etc. (Especially with regard to caves or other mostly-enclosed structures, using DIFs can greatly improve performance over similar DTS structures because you can take advantage of the DIF's capability to be portalized and BSPed.)

My general rule is this: Use DIFs for things you can go into or inside. Use DTSs for everything else.

Allyn "Mr_Bloodworth" Mcelrath (Aug 21, 2007 at 18:32 GMT)

How are you going to do collision on this?

Ben Acord (Aug 21, 2007 at 22:29 GMT)

Constructor handles the collision details on export to DIF. However, in Blender -or any other modeling tool- it's a manual process.

Allyn "Mr_Bloodworth" Mcelrath (Aug 21, 2007 at 23:48 GMT)

i know this, but collision on DTS has some limitations, and was wondering how you were going to provide collision on such complicated objects.

Don Hogan (Aug 23, 2007 at 02:21 GMT)

@Allyn: Everyone seems to fear creating collisions for complex DTS shapes - it's not hard, it's just boring as all get out.

Personally, if DTS shapes had the same level of shadowing as DIFs, I'd take them as my first choice just because I'm so slow with brush based editors and find them horribly limiting. (I'm also the first to admit I've been spoiled by the engines I've used so my opinion is heavily skewed.)

Ben Acord (Aug 23, 2007 at 12:57 GMT)

I fear modeling brush based organic objects more than manually assigned DTS collisions.

All of my cliff and cave sketches have a basic structure that would work great as a brush-based DIF...but without the natural look it would clearly be a brush based cliff. I want to find that happy medium where the objects collision, structure, shadows, etc. are driven by brushes but the details are DTS meshes (as Kevin Rogers has pointed out). This is something that I haven't done before -combining structure and detail- so I'd welcome any experienced feedback. Right now there are several tests of a single type of cliff that I'm playing with to see which method I like best.
Edited on Aug 23, 2007 12:59 GMT

Allyn "Mr_Bloodworth" Mcelrath (Aug 24, 2007 at 20:17 GMT)

@ Don - Its not the creation of them thats the problem. Its the limitations of them. Complex collisions on DTS are performance hits, also, you can only have 8 for any one shape (say 8 squares on a chair), and they still must be convex for true performance (FPS and reliability of collision).

My main concern is cave like structures. I have made cliffs and other parts such as covers for cave openings, but with a streamlined collision and forethought of where a player can and shouldn't get to.

Its all a fine balance, but with this current engine, i wanted to know how he was going to approach the collisions on some of those shapes.

Every cave i have created is a combination of Terrain, DTS (Transition) and DIFF (blocky interior areas), with DTS details (rocks torches ETC). The is also the visibility considerations with using large DTS objects.

Don Hogan (Aug 24, 2007 at 22:08 GMT)

@ Allyn - I certainly understand, and I'd most likely go at it the same way you describe - as I said, I've hand built collision under similar constraints for almost 8 years, so I have a different view on it. I guess I'm resigned to the process of the balancing act. =)

I do want to point out, however, that with the current MAX exporter I'm exporting far more than 8 collision shapes successfully.

Woody (Oct 30, 2007 at 18:00 GMT)

I would like to also mention that with the current Maya exporter, I have a couple of objects (stairs/railings) that have many more than 8 collion meshes too. We don't notice a performance hit there, but it's only a couple of objects. Anyway, with terrain, I would guess that you may want to separate it out into many pieces for the collision "limitations" that exsist... knowing that you will also likely see hard edges (un-smoothed normals) and possibly light seams between the pieces.

I'm currently working on caves, essentially (underground mine). They are a bit more blocky than some of the great caves you may find in games, but slowly I'm getting it more organic looking... all using DIF. Trust me, these would have been done a LONNNNNGGGGGG time ago if it were DTS. The great thing is that the lighting is very good (we're using a psuedo-flashlight) using DIF, versus the vert-coloring that we would get with DTS caves. The downside is first and foremost the time it takes to oganically model in DIF format, but also that there's no way to tell when adjacent pieces will be smoothed together or not, or if you'll see a seam. But with clever texturing, you may be able to get some nice results.

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