Tutorial: How to Check Polygon Counts of Objects

[baratron]

As people keep asking, I thought I'd copy all of the information that's scattered around the forum about polygon count into one thread, with links back to the original posts. I assume no one'll mind . This first post is mostly by me, and I'm sorry if it sounds patronising. I'm trying to explain something complicated in simple enough words for everyone to get it - which means, inevitably, that some people will read it and roll their eyes because they know it all already .

About Meshes
In Sims 2, there are three basic types of user-created objects:
1) Hacks, that modify the game's code.
2) Objects, including furniture, clothing & all genetics, that are recolours of Maxis-made objects.
3) Objects, including furniture, clothing & all genetics, that are not recolours of Maxis objects.

Objects in category 3 have been made using a 3D modelling program, such as Milkshape or Wings. They have a new, customised shape that did not previously exist in the game. This 3 dimensional shape is called a mesh. The mesh by itself is useless - it's just a shape. To make the object look real, a texture gets added, which is the flat picture that gets stuck onto the mesh to give all the details.

So What's the Problem?
Unfortunately, there are a very large number of 3D programs in existence, and none of them are perfectly optimised for Sims 2. Some of them are designed for game or movie modelling. But some of them are designed for what's called static modelling - in other words, when you make a scene on your computer, and it doesn't animate. Meshes that have been made in this way might have absolutely enormous polygon counts, and it doesn't matter because they're not designed to animate. However, Sims 2 relies on animation - people move around and interact with the objects in the game. If you have a lot of high polygon meshes in the game, then it will make the game slow down. The reason is that your computer is having to render complicated objects as well as doing all the usual things that happen in the game, and it only has a limited amount of resources to do all that with.

What is a Polygon anyway?
A polygon is a flat shape with edges - like a triangle, square or parallelogram. All 3D meshes are made up of a very large number of polygons. As a general rule, flat, square objects need very few polygons compared to curved objects. But you can't tell by looking at a photo of the object how many polygons it uses. Some creators know how to optimise their meshes and use tricks with alpha channels to reduce the polygon count dramatically.

In Sims 2, all of the polygons are triangles. The corners where the triangles meet are called vertices. Maxis has a guideline that they use for their own objects of 800 vertices per tile. (See long thread at Mod The Sims 2). 800 vertices means 800 corners, which is not the same thing as 800 polygons. However, there isn't a simple relationship between vertex count & polygon count - some meshes come in at 1000 polygons, 800 vertices while others do 600 polygons, 800 vertices. My geometry is too rusty for me to work out why .

So when it comes to Sims 2 meshes, we should really be talking about high-vertex meshes being bad, rather than high-polygon. I don't know why we don't, except that polygon can be abbreviated to poly, which sounds a bit friendier .

What is a Good Vertex Count?
Using Maxis' guideline, we assume that objects "should" be as follows:
1 tile - 800 vertices
2 tiles - 1600 vertices
3 tiles - 2400 vertices
4 tiles - 3200 vertices
5 tiles - 4000 vertices
6 tiles - 4800 vertices

In practice, a (6 tile) double bed with 4800 vertices will slow some people's computers down, while other people will be fine with a (1 tile) cupboard with 6500 vertices - but that's a reasonable figure to work to.

Also, as Motoki said (on November 14, 2005, 12:48:34 AM):
The tile guideline as far as I know was more to give a higher limit to larger stuff than anything technical to do with the number of tiles use. It's a decent guideline but you also need to take other things into account like the relative size and complexity of an object too. I would be more lenient to say a large complex one tiled statue than I would be with a tiny flower. Also relatively simple boxey or squarish objects shouldn't need to be high poly at all no matter how many tiles they take up. A large plain 3 tiled flat square poster does not need 800 vertices per tile and shouldn't be anywhere near that count.

A better guideline is to compare a custom object to a Maxis object of the same type. If Maxis' piano needs 3300 vertices, and your custom one of the same size is using 3500, that's not too bad. If the Maxis object is on 3300 vertices and your custom object has only 2800, that's really good!

What about Things that Go On the Sim?
No one seems to know what vertex count Maxis use for hair and clothing meshes. Next time MaxoidTom or someone else shows up here, we need to sit on him until he gives us an answer!

Regarding hair, Motoki wrote (on November 09, 2005, 03:51:35 PM):
This is kind of my guidelines, so take it with a grain of salt, but I would say for the face count:

under 1k = great, no problem
1k-2k = pretty good
2k-3k = not too bad, but might want to use sparingly
3k-4k = kinda pushing it, use sparingly
4k-5k = only use if you absolutely love it to death and try not to give it to more than one sim on a lot if you can help it.
5k+ = too high

You can get away with ones with higher counts sometimes without problems, but remember it's not necessarily the one mesh that will cause problems alone (well unless it's like 30k+ faces ) but moreso the cumulative effect. Consider the fact if you download a lot of other stuff it will add up and some of the Maxis stuff itself isn't always super low poly. Also try to think about the type of family you will be using the hair with. A single sim in a small starter home might not have problems with a high poly hair, but later on if she gets married and has 6 kids and moves into a huge mansion on a large lot with a bunch of junk it's not going to help the game run any faster that's for sure.

Also, if you are putting custom hairs on townies try to be mindful of the counts and avoid putting high poly hairs on them. A bunch of townies all on the same lot with high poly hairs could be asking for trouble. At least in my game those community lots, particularly the downtown ones, run slow enough as it is and don't need any help.


I tend to assume that anything under 1500 polygons is ok for hair and 2000 polys for clothing. This can give very reasonable-looking hairstyles. For example, Crammyboy's very detailed two hair meshes for men (short messy hair & flat top hair) come in at almost exactly 800 polygons because he's used multiple layers to achieve the spiky effects.

In the next post - How to actually check the polygon count. To come after dinner. (Sorry, but I'm not letting my dinner get cold just because I'm posting to MATY!)

[baratron]

This post lifted in its entirety from SaraMK (on November 15, 2005, 10:51:16 PM)
I use DatGen for this. It has a feature called Download Maid which has an option to look for poly-heavy meshes. It will scan your entire Downloads folder and find the ones that are potentially a problem. You then have the option to quarantine them to a new folder, which will then allow you to open each one individually (if necessary) and decide how to deal with it.

DatGen does not tell you the exact poly count. What it tells you is how much more than recommended a mesh is. For example, it can tell you that an object is 4 times the recommended/safe amount. Now, when you open that object, it might turn out that it has something like 2000 polygons and it's a really, really cool object that you don't want to do without. 2000 is not THAT bad, as long as you don't use a ton of them on the same lot, so you might decide to keep it. But an object that shows up as 19x more than recommended will probably have something like 25,000 polygons and must be deleted immediately. Screenshot http://i26.photobucket.com/albums/c129/saramkirk/datgenpic.jpg

So you will still have to use SimPE to open each file individually, but DatGen can at least tell you which files you need to look at and which ones you don't need to look at at all. Much better than just opening every single file blindly.

Where to get DatGen: http://www.datgen.info/downloads.aspx

Next post: What to do with SimPE.

[baratron]

Unfortunately, using SimPE to scan a whole load of files isn't so easy.

Motoki said on November 16, 2005, 02:07:33 AM:
It does, you can go to tools, then scan folders and then in the scanner settings tab uncheck everything but the health scanner. When the scan is done sort by type and look for the stuff flagged as high poly. It will also scan for other problems too.

but this doesn't seem to work with the current version (0.50). At least, I have a one-tile cupboard that I know has 6536 Faces (Polygons) and 4296 Vertices, but SimPE's Health Scanner didn't flag it as high-polygon.

So you're left with opening each .package individually . Yup, this is a pain. But remember, you only need to check the polygon counts of objects that use a new mesh. Anything that's a recolour of a Maxis object, or a recolour of a mesh you've already checked, is ok.

* For objects, the mesh is included in the same .package file as the texture.
* For hairstyles, clothing & accessories, the mesh is in a separate file that usually has a name starting MESH_. There's no need to check the texture files of hairstyles, clothing or accessories, because they don't have any polygons or vertices in .

In SimPE,
1. Go to File --> Open and choose the .package file you want to check.
2. Under Resource Tree, there should be a list of resources. If there isn't, click the + sign next to All Resources to expand the tree.
3. Click on Geometric Data Container (GMDC), first in the Resource Tree, then again in the window next to it. The information will load in the Plugin View.
4. Look down at the Plugin View, and make sure the tab labelled cGeometryDataContainer (the first one) is open. Beneath that is the word Models, with a Face (polygon) and Vertices count.
5. Compare these numbers to the ones given in the first post. If they're lower, rejoice. If they're a lot higher, consider removing or disabling the object from your Download folder.

Note:
1. Many objects have multiple meshes. You need to look at the added-together values in bold at the top.
2. The exception to this is if an object has multiple states, such as normal & broken. The broken version might use a different mesh. As the object can only be in one state at a time, you only need to worry about the normal value.
3. Some hairstyles are available for different ages, using a different mesh for child, teenager and adult. You'll need to check all of the possible meshes, although I don't actually seem to have any examples that use more than one custom mesh (the other age groups are done on Maxis meshes, presumably). But again, remember that the sim is only one age at a time .

I hope this is detailed enough to help! Oh, one more thing. Again, quoting from the same Motoki post as above:

question I have, though, is, is there or is there not a relation between polygon count and file size?  If there is, then that should help pinpoint the more urgent files.

There's not an easy answer to that question. High poly meshes all other things being equal will be a larger file than a low poly mesh utilizing the same texture, and in general the higher poly meshes seem to be larger file sizes, but mainly what takes up the most space in the package files are the textures. So a very low poly mesh with a large and detailed texture file will be a large package file, conversely a high poly mesh with a small or single colored texture could be a smallish file size.

In short, no it's not a good way to tell.

[Ancient Sim]

This is very useful.  I've just run Download Maid and apparently Bathroom Uses You is a very high-risk object.  Unfortunately, as I always do I have error after error with DatGen and it won't actually work properly, so I can't move anything to check it.  Don't know what it is about that program, but it never works properly for me.

[angelyne]

Thanks again for this tutorial.  Now that I understand what a vertice is, I can be on the look out for potentially high poly objects.

Is this the kind of objects you warned us away from ?

Models(Faces=1584,Vertices=14281) ?

[attachment deleted by admin]

[baratron]

Is this the kind of objects you warned us away from ?

Models(Faces=1584,Vertices=14281) ?

15484 polygons? For a painting? Which presumably is a mostly-flat object hanging against a wall?!

Indeed, yes - that is absolutely the kind of object you want to remove from your game! I almost feel that it needs a public naming-and-shaming so we all know which site to avoid.

Ancient Sim, I just opened Bathroom Uses You with SimPE. 5280 faces, 4358 vertices. For a 1-tile object, that you'll have multiple copies of in each lot ! Yikes. We have to seriously do something about this. It's way too high spec for what it is. Although nowhere near as much as angelyne's painting.

I see in the rtfm that the mesh was made by Queen at VS. Hmm. Why am I finding myself now unsurprised by the polygon count? Hmmm.

[SciBirg]

Are there any talented meshers here?
Does Dylan do meshes yet? Maybe he could fix it?

[Oddysey]

Variousimmers? Home of Miss Ren "Polygon Counts Don't Matter!" tech? Why should we expect anything less? </uncalled for sarcasm>

There's got to be someone here who does meshes. Heck, I've abused myself with it in my spare time. 'twas a spline program, so I deeply fear the results of trying to convert something into a polygon format. Hmm. I think I remember some sort of toilet paper art object created for some demented lunatics realism purposes.

What we need is some sort of MP Spanish Inquistion type force to beat people who make massive meshes with pillows. It's all in the texture, people! There's an artistry in a simple mesh. A lost art, like tight coding and spell checking, but an art none the less.  </uncalled for rant>

[baratron]

Crammyboy rocks.

Go & download the new versions of Bathroom Uses You and the Baby Controller. Bloated meshes replaced with nice, neat, low-poly versions. (I think he said his Bathroom Uses You mesh has 142 polygons, which is really low).

[angelyne]

Oops haven't checked on this thread for a bit.

No, the object wasn't a painting, but a baby mobile.  After reading your most excellent tutorial and UNDERSTANDING finally what it's all about, just looking at the object was enough to suspect it had a high poly count.

I checked it and lo and behold I was more right that I thought.  It was part of  really pretty nursery set over at TSR.  But almost every one one of her meshes was high poly, although the mobile was the worst.  The second worst was a baby bath. I had to get rid of rid of half of her meshes, which was a shame, as it was a nice set. To be fair, I think this was done in the early days when new meshes started coming out, so she wasn't probably aware of the problem.  I notice that some of the creators at TSR are listing their poly count, and even warning people to consider the fact their object is high poly.

Addendum:  Is there anyway to find out how high poly Maxis Objects are?  I know some of them are high'ish.  I most especially suspect the blinds. It matters to us poor people afflicted with a sucky video card


PS.  Crammyboy does rock.

[IgnorantBliss]

Addendum:  Is there anyway to find out how high poly Maxis Objects are?  I know some of them are high'ish.  I most especially suspect the blinds. It matters to us poor people afflicted with a sucky video card

You can do that by cloning the Maxis object in question (you can uncheck all the cloning options since it's not a clone you're going to use for anything).

[Po]

This is always good to read again, thanks.

As an apparently casual gamer, it drives me batsharf insane that someone would make such high poly count items in the first place, considering that they are so into the game and/or making stuff that they should know better. 

To a large extent, I really am depending on other people to do the helpful thing by alerting gamers whenever a polygon hog is found.  Not sure if this is still a problem, but considering humans are kinda pesty critters, it wouldn't surprize me.

I remember Reflex Sims was supposed to be really bad about it at one time.  And sims2ellis.narod.ru,  if they haven't improved.

Any others I should know about?  In particular, any others at TSR?  I've noticed they're not listing counts like they used to.

[Venusy]

{{necromancy|bad|m'kay?}}

Oops. Wrong website.

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