Difference between revisions of "Game Help:Poly Counts"

Revision as of 11:49, 13 April 2007

What are poly counts? What's a good or bad poly count?

Poly counts

As you begin downloading content, you'll run into a lot of info you may not recognize. Among the info often given on new mesh uploads is what is known as "poly counts."

"Poly" is short for "polygon." Polygons in The Sims 2 are all triangles, three points connected by a plane. So a "poly count" is simply the quantity of polygons in a 3d model.

• A polygon can be any size - extremely tiny, or as big as a house, but it's always three points connected by a flat surface. This is a single poly, one triangle:

• In a 3D model, one can assemble polys in all sorts of different ways to create any sort of shape. Generally, shapes that are flat, with straight lines and angles use less polygons than shapes that are curved or rounded. See how the cube has so many fewer polys than the cylinder or sphere?

• The more complex the item, the more polys you would expect it to have. An extremely complicated, curvy item would be higher poly than a very simple item that basically boils down to a few cubes or planes.

• Almost everything in the game is made of polys - from your sims to their clothing, hair, and accessories, the house itself (and its doors, windows, roof, and all of its furnishings), even their cars and pets... all of them are made of polygons.

• You may also see vertex/vertices counts (often shortened to V, vert, or verts). That's simply the number of points in 3D space in the model - how many points they use to create however many polys there are. It's often listed alongside, but you mainly need to pay attention to the poly count.

Why do poly counts matter?

Poly count can be very important. Inside every computer is a graphics card - it's the part that makes all the pretty pictures. The graphics card has to plot the position of each and every poly in 3D space. It also has to render the surface of the poly itself... and all the textures, and any special properties like reflectivity/shine, and any transparency like cut-out strands of hair.

Every poly you add is just a bit more strain, more work for your graphics card to do - and it has to do it every frame, continuing to render all those polys as the game goes on. This can generate a lot of heat, and a lot of stress on your graphics card, especially if it's not incredibly good.

The effect of polys is cumulative - one high poly item generally will not cause problems. But if every item you have is high poly, or you use a specific extremely high poly item over and over, you can begin to experience problems like:

• Lower frame rates - The game gets choppy and slow.
• Slow scrolling - It's slow and difficult to move across the lot.
• Slow zooming - It's slow and difficult to zoom in and out.
• Game freezes - The game stops responding and has to be forcibly closed without the option to save.
• System freezes - Your entire computer locks up and stops responding. You have to shut it down using the power/reset button.
• Graphics-related errors - You may overload your graphics card, crashing the game, dropping you to a lower resolution, and forcing you to reboot/shut down.
• Graphics anomalies - An overstressed graphics card may begin displaying gaps in hair at the forehead or back of the neck, sparkles and strangeness in other meshes, blurred textures on sims and objects, blurred/crunchy/shredded thumbnails, blurred mirrors, or other display-related weirdness.

Needless to say, any of the above is bad, and if you begin seeing increasing signs of stress, it can be a sign your graphics card is being overstressed. Overstressing a graphics card may eventually cause it to fail - you'd have to purchase and install a new one (or get someone to install it for you), which can be pricey.

This is also not to say that all of the above is always caused purely by high poly content and related problems... You may just have a crappy graphics card... Or it may be overheating because of dust/dirt/age/lack of proper cooling... Or you may need to update your graphics card's drivers to fix certain issues... Or your graphics card may just be having its own strange issues...

But all of the above -can- be caused, at least in part, by the stress put on a graphics card by having to render too many polys.

What is a good or bad poly count?

The answer to that is a little complicated. Basically, it depends on the item, and how special it is. For different types of items, you would expect a different poly count, and for more complex ones, you would expect a higher count.

• For objects, Maxis gave us a guideline of around 800 polys per tile, but that's a very fuzzy guideline that they exceed themselves on numerous occasions. It has to be balanced based on the detail and usefulness of the object - a very simple boxy sofa probably shouldn't be 800 polys per tile, but a very fancy one could push higher than that and be just fine.

• For an item you would use over and over on a lot - like a dining room chair, you would want as low a count as possible. For a very decorative item you would only use once, you could go a little higher. The upper limit for objects is around 2000 polys per tile - it'd have to be VERY special to be much higher.

• For body meshes, anywhere from around 1600-2500 is within expected normal ranges. Higher than that, the mesh would need to have a lot of necessary detail to warrant a higher count... Alpha meshes can often push higher. The upper limit for everyday use would be around 3000 polys for clothing/bodies (that's a full body, not separates).

• For extremely special items like runway fashion, you can go higher - you'd only use them once per lot, and rarely. The Atlaua peacock dress is somewhere around 12-15k polys, which is extremely high, but the level of detail is warranted, and one would likely never put that on more than one sim at once.

• For hair, Maxis meshes range from around 500 polys for really simple short male hair to about 3000 for more complicated female updos with funky stuff on them. Most everyday-use hair should range from 1000-2000 polys, with extra-detailed, curly, or special hair going up to about 3000 polys. Hair would have to be -very- special and used very rarely to push much higher, the upper limit being around 5000 for something incredibly special and complex in shape.

• For accessories, it really varies, but probably about the same as hair in terms of ranges for usability.

So how do I decide whether to download a high poly item?

It comes down to you and your system, and how much you think you'll use it. If you do choose to get some higher poly items, remember which ones they are. Use them sparingly, try not to use them together at the same time, and if you start experiencing issues, try taking them out.

With poly counts, try to think of it like you're paying for polys. How much are you willing to pay for a particular item? Is it special enough to warrant its high price? Or is it a simple, boxy item that's "overpriced"? Are you going to need to use 50 of them on a lot? Will you be able to afford all of them that you're going to want to use, or will you have to be more sparing with them?

What if there's not a poly count listed?

Ask! If you're downloading a new mesh, the creator should have a poly count listed. If they don't, well, honestly, you should probably be a little suspicious. It's possible they didn't realize they should list it for downloaders, they forgot it, or otherwise...

But many times, if a creator consistently doesn't list a poly count, it's because they're not paying attention to the poly count as they make their meshes. The Sims 2 is a low poly game, so if someone makes an item without care to how many polys they use, they can create something that will cause problems for downloaders... and not even know it!

If you can't find a poly count listed and can't get an answer from the creator... either don't download the item, or use it at your own risk.

How to find your poly count and what is reasonable

As people sometimes get lost - this is how to do it in SimPE:

• Open up your mesh file in SimPE

• Click on the Geometric Data Container in the Left Window

• Click on the Geometric Data Container in the Right Window

• The plugin view should appear at the bottom of the screen, if it does not, click on the plugin tab and get that to show

• FACECOUNT = POLYCOUNT

• If your creation has more than one Group/Subset, the polycount is ALL of them added together.

See examples below:

What is a reasonable poly count?