Complex Models (few objects) VS Models with Many Object

Greetings,
I am curious if anyone has done any tests to compare how well different types of models work in MSTS. Mainly I am wondering if more complex models with few number of objects (children) will affect FPS rates any more or less than having a less complex model with many objects (children)?? Or is how the model put together not really important in MSTS in regards to FPS rates??
Not sure if it is important or not, but I am using 3D Canvas.
Any thoughts or ideas?? Thanks for your time and good day!Mykel

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RE: Complex Models (few objects) VS Models with Many Ob, pwillard, Sep-16-03, 01:48 PM, (1) RE: Complex Models (few objects) VS Models with Many Ob, johnf, Sep-16-03, 03:22 PM, (2) RE: Complex Models (few objects) VS Models with Many Ob, Vulcan Foundry, Sep-17-03, 00:08 AM, (3) RE: Complex Models (few objects) VS Models with Many Ob, decapod, Sep-17-03, 05:38 AM, (4) RE: Complex Models (few objects) VS Models with Many Ob, mjs2101, Sep-17-03, 08:44 AM, (5) RE: Complex Models (few objects) VS Models with Many Ob, pwillard, Sep-17-03, 08:57 AM, (6) RE: Complex Models (few objects) VS Models with Many Ob, Captain Bazza, Sep-18-03, 00:51 AM, (7) RE: Complex Models (few objects) VS Models with Many Ob, lnghairedwizard, Sep-18-03, 02:40 AM, (8) RE: Complex Models (few objects) VS Models with Many Ob, mjs2101, Sep-19-03, 12:43 PM, (9) RE: Complex Models (few objects) VS Models with Many Ob, pwillard, Sep-19-03, 01:09 PM, (10) RE: Complex Models (few objects) VS Models with Many Ob, mjs2101, Sep-20-03, 11:11 AM, (11) RE: Complex Models (few objects) VS Models with Many Ob, pwillard, Sep-21-03, 02:56 PM, (12) RE: Complex Models (few objects) VS Models with Many Ob, mjs2101, Sep-27-03, 04:09 PM, (13) RE: Complex Models (few objects) VS Models with Many Ob, awaken77, Oct-09-03, 04:48 PM, (14) RE: Complex Models (few objects) VS Models with Many Ob, mjs2101, Oct-10-03, 12:49 PM, (15) RE: Complex Models (few objects) VS Models with Many Ob, Vulcan Foundry, Oct-12-03, 07:21 AM, (16) RE: Complex Models (few objects) VS Models with Many Ob, pwillard, Oct-12-03, 10:30 AM, (17) RE: Complex Models (few objects) VS Models with Many Ob, xlspecial261, Oct-12-03, 04:43 PM, (18)

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I've personally had more trouble with complex models that have all of their parts joined so there are fewer total parts versus small number of "base" parts with many children. You mileage may vary, but I encountered the "UID 200000" problem more often when I was trying to "clean up a model" by reducing part count.
Pete Willard
http://www.trainsimstuff.com

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yep, more parts has also provided me with less uid errors as well. Th e other thing is to reduce face intersections.

john fowlis

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LAST EDITED ON Sep-17-03 AT 00:10 AM (EDT)

Generally the fewer the groups the better performance within the sim. However that being said and having been caught before try and keep each the triangle count within each group under 3000. Sometimes with 3D Canvas this is not possible to accomplish and with more complex models you may just have to use more groups.As for exact performance (FPS) vs the number of actual groups used to create a model in 3D Canvas, I don't think anyone has really done any exact calculations other than personal observations.Paul Gausden would probably know the exact answer to this question as he, to my knowledge has built more models with 3D Canvas than anybody.

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I've not built that many models (about 20 steam locos + others bits), but I do have a grounding in 3D game programming...Basically, fewer groups (in 3DC) is good for efficiency, but MSTS doesn't like it much if the sum of the triangle count of all objects in a group goes above 3000 (use the count triangles script or plugin)
In 3DC the number of objects in a group doesn't matter as they all get combined into similarly textured "sub-groups" (primitives) in the end.Also good for efficiency:
- solid BMP textures, transparencies have to check the depth buffer. However given the choice between low poly count and using transparency - keep the poly count down. Just use BMP textures where you can.- DXT ACE format - much more efficient on some video cards
- fewer ACE files. re-use of texture areas is the key here, though it makes repaints harder.- wrapping and smoothing textures - this effectively creates one vertex (a point, texture coord and normal vector) per point - creasing gives two normals, hence two vertices.

Paul
UK GWR Highworth Branch
http://www.highworth.freeuk.com

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Thanks for the replies!! Definitely helps with the building process, but will have to recheck some models for the 3000 polys per group. (maybe I can eliminate some of those UID errors) As for the texturing, is it better to have parts that require alpha's to be on a seperate .ace file, or can they use the same .ace as the rest of the model and run just as efficiently (keeping the groupings seperate)?Thanks again and have a good day!!Mykel

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LAST EDITED ON Sep-17-03 AT 09:03 AM (EDT)

Keep Groupings and related mapping of ACE files together. IE; Group- Longhood main part - PART1.ACE
Children (everything attached to the longhood) Done so that all child parts of the "longhood" group are also in the same ace file. This seems to prevent problems with LOD.I've found that if I use alpha channels, I try to make sure that all visible ajacent parts either come from the ACE file with an alpha channel or create an alpha channel in the texture the adjacent part comes from so there isn't a variation in the color depth.If your "cab" ACE had Alpha channels and your "longhood" ACE does not they may not look like the same color next to each other when run in the sim due to the way the SIM adjusts colors to make up for the ALPHA channel.
Pete Willard
http://www.trainsimstuff.com

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I love creating complex models. The hit on frames is not dramatic, but of course very long consists will have some effect, depending on the camera POV. A current project, a railcar, has over 16,000, without a problem. I very rarely use alphas or transparencies for windows. I look forward to the challenge of using much higher poly counts in MSTS2.

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RE: "I look forward to the challenge of using much higher poly counts in MSTS2."I do too, but I'm not holding my breath for such an improvement in capacity.Longhairedwizard

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Thanks again for the replies! I was not aware of the color distortion between alpha'd and non alpha'd items!With this in mind; when doing a baywindow caboose (extracting the overall shape, roof/sides/ends/bottom, from a single simple cube), with sides and ends using alpha channels and the roof and bottom not, would it be better to create the model with the roof and bottom separate from the sides and ends? I know in using 3D Canvas that if you use alphas on the sides and ends, then you also have to use the alpha option on the roof and bottom as long as everything is one object. Just curious if it would benefit in game performance on a caboose with 3400 polys (w/optimized LODs down to 120 after 700m), to seperate these parts so it uses less alphas? (hope this makes sense)Now if only I can find the time to finish up the projects I have going.
Thanks again and good day!Mykel

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RE: "hope this makes sense"DARN. You lost me. "would it be better to create the model with the roof and bottom separate from the sides and ends" If you are extruding from a main cube, and therefore have a single object, then use a single alpha'd texture map. That would be the most efficient, regardless of whether it's the ends or the top or bottom.If you extruding all the faces from a common object, you are aware that you will have extra faces "inside" that you might want to remove.
Pete Willard
http://www.trainsimstuff.com

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AH, figured this would happen. Basically, I was talking about building the model:
1) Should I build it so that the roof, sides, ends are extruded out of one single object, which means that the entire object would use alpha'd texturing...... or
2) Build it and create the sides and ends out of one object and then create the roof and underframe from another object so that only the sides and ends use the alpha'd texture while the rest uses just plain texturing.
Would there be any benefits for using one over the other?Yes, I try my best to keep track of any "unseen" faces. Sometimes easier said than done.

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Personally, I create as many parts as I need to make it look right... without resorting to using ALPHA maps right away.For example: when I started creating the end details, I really didn't like the way the ALPHA mapping looked, so I opted to do low poly tubes to create the details. Adds a few poly's, sure, but the overall effect is better...It bumped it up to 1400 poly's, but I hate to lose the detail. I like it so far, so I'm going to heep it.

Pete Willard
http://www.trainsimstuff.com

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Excellent model you have there Pete!! and at only 1400 poly's... WOW!!One thing I was wondering.... On the previous models I did, and ones I am working on, in doing the trucks/wheels, I used an alpha channel to represent the tread on the wheels and save a few poly's. (basically saving 24 poly's per wheel set or 96 for the whole model - using a cylinder with 12 sides for doing the wheels). So in this situation, would it be better to have the higher poly count and fewer alpha's??
Sorry for my many questions, but I am just wanting to get a clear understanding of alpha's vs poly count and efficentcy. Basically the models I am working on lie between the 1700-2500 range, and while I have been keeping the objects simple and keeping anything using alpha's seperate, I was wondering if I should redue the trucks and wheel sets?Thanks again for replying and have a good weekend!!Mykel

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You can do highly detailed model without hitting performance hard if use LODs extensively. For example transparent windows, handrails, detailed undercarriage,internals of passenger cars for nearest distance only. no handrails, windows, less undercarriage for 200m and so on. Nobody will see it anyway but it will slow down sinulation in long consist. and for 2000m it's just a plain textured box or like this.
I have 1516 polys per car for 100m, 586 for 200m, 50 for 400m and 18 for 2000m.

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Unless this has changed with an update, 3D-Canvas does not let you adjust LODs, you simply get what it exports. It would be nice if you could assign diffent objects a specific LOD.
The models I am working on are in the 2000-2800 range, and using LODs to help with distant views.
What program do you use that allows you to set specific LODs for a particular object?
Thanks for the reply! and good day!Mykel

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Try Shape File Manager.http://www.railpage.org.au/steam4me/trainsim/tutorials/sfm_faq.htmlIt will allow you to adjust Distance levels based on the number of LOD's you exported the shape file with.

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We have asked Richard at Amabilis for this ability. He spent a lot of time tweaking the "wizard" and didn't really want to re-visit it until he was done with other feature "adds". He thought the LOD options were good but we might have impressed upon him our desire to have more LOD options.
Pete Willard


http://www.trainsimstuff.com for beta releases, fonts, and project news.

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I've had nothing but problems with LOD's in 3DC. Never got one to export yet.I do need to go back and make sure I have things textured off of the same ace and such, but I don't think that is the problem.About the only time I have gotten an UID error with 3DC is exporting with LOD's.Todd

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