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A generic question about Mesh details

Hello everyone,

I am quite a beginner in terms of creating own content for my (formerly UDK and now UE4 :slight_smile: ) projects.
My question is: How many Verts/polys should a static mesh typically have?
I know there is no software limit per se, so the hardware sets the limit, but what would be a reasonable figure?
If I make a mesh with 20k polygons and place it 5 times in the level, would is be as “expensive” as having one 100k model in the scene?
How many polygons do you generally spend on ubiquitous items like chairs, picture frames, pipes, etc?
The intended target is not mobile or console but strictly PC.

Hope the question sounds not too stupid :slight_smile:
Cheers,
Klaus

There’s no way to know, it depends on so many things, design, style, the amount of other things going on in the level, and what you personally are OK with as far as detail.

For ubiquitous items, like chairs, I would be aiming for the hundreds of polygons, personally. A lot of small details can be handled with maps. You can even bake the information from a high poly model into various maps to use on a low poly model, which is pretty common. I think the questions you might want to ask yourself are, “How close is the player going to get to this object, are they meant to pay attention to or examine it, and how important is it compared to other objects in the scene?”

For example, a throne which the character is meant to walk around, examine closely, interact with, etc should be modeled and textured with a much higher fidelity than a folding chair you’re going to populate a mess hall with. The throne could almost be considered a character, depending on how important it is, whereas the folding chairs are meant to just be run past without giving them a second thought, and most of the time they will be. There will always be that one person who will squish their face right up against that folding chair, but as a dev working by yourself or on a small team you have more to worry about than modeling every dent and texturing every mustard stain on the seat of a chair instanced fifty times in one room. It’s all about priorities, not just in optimizing the game, but optimizing your time working on the game.

Hi Klaus,

This is really a subjective question because there are many factors that go into this decision. Is it being developed for Mobile/PC/Console? Is this a hero prop (player will interact or use a lot) or background prop? How often will this prop be used?

There are a lot of questions that could go into this. This was always the first questions asked when I was in school. We weren’t told specific limits because you cannot set specific limits on something like this. It’s a process of keeping the poly count as low as possible while still making sure you give it the detail it needs to look good. For newer users to 3D modeling this can be a nightmare because they want hard limits to target.

The best solution is to set limits for yourself once you get comfortable modeling. Right now, don’t be concerned with getting it to a specific limit and instead model your object and then when you’re done before you start the Unwrap for the UV start going through and removing polygons and edges that you don’t necessarily need.

I’m going to give you some limits you can choose to use or not, but at least this will give you a goal to stay under. These are just references and not definitive. Use your best judgment and if it need to be lower do so. If it needs a little extra detail, do so. :slight_smile:

For small objects: (ie. water bottle, cups, books, etc.) <75 polys
For medium objects: (ie. chairs, book shelf, lamp, Barrel, etc) somewhere between 100 - 1000 polys.
For larger objects: (ie. car, buildings, house, character, etc) 1000 - 10k polys (this is really subjective here. Depends on the project!)

Some may disagree with me, and I may disagree with me on these numbers because it can depend on an object to object basis and how it’s used.

A good exercise is to start looking at objects in games and see which ones got more detail! A good example I can think of where I last did this to great extent was with Bioshock Infinite! This is a beautiful game and when you look at the hero pieces or larger set pieces it’s fantastic, but when you start looking at the smaller objects in corners or used as decoration that most people walk right on past you can see that the poly count on these objects are much lower. This is because players aren’t going to necessarily stop and look at every object. The designers/artist knew this and did not worry with wasting time there.

The 20k would be more expensive than the 100k object. The reason behind this is, depending on how that object is lit and shadowed can greatly affect your scene. First off, there is probably no need to use a 100k object in your scene. a 20k object would probably be along the lines of a highly detailed character. If you look at the elemental demo I believe that character was somewhere in the 20-40k range. I can’t remember exactly right now.

The reason five objects at 20k would be more expensive than one 100k object is that you have a separate draw call for each one of those meshes. If it’s using the same material/texture this will reduce that but you’ve got five objects vs one object.

There are other factors that play into this as well. How are those five objects being lit? If they are using Dynamic lighting and casting dynamic shadows this can be expensive. While dynamic lighting is very efficient in UE4, using dynamic shadows will definitely give you an impact.

There are some other factors that can affect the scene as well but most of this information should give you at least some places to start.

If you have any questions feel free to ask!

Tim

Hi All,

Thank you for your input :slight_smile:
Indeed, I tend to treat folding chairs etc. like hero pieces. That image of fiddling with mustard stains is not far from true :wink:
If I follow Tim’s sggestion (and I know its only a suggestion but deliberately choose to follow it), I need to focus less on detail.
Which is going to be tough since Im a detail fetishist… Thus a simple metal coffee mug has 500+ polys, definitely too much.
That is, after modeling it in 3dsmax with some beveling, denting it in zbrush and then fine tuning it in max again…
I guess what cynical coffee said is true as well. The dents could be achieved with maps.
But would the rim of the dent cast a shadow in it when the mug is lit from the side? (detail fetishist)…
Maybe my “excessive” use of polygons might be due to my lack of expierience in what maps/shaders can achieve. But I’m learning.

It is a nice expierience to find constructive answers and help here in the forum.
Thanks again :slight_smile:

Cheers,
Klaus

Cheers,
Klaus

Rule of thumb if it needs to look round make it look round that supports the materials being applied.

If you have an oil drum that looks like you can turn it with a wrench your not there yet.

Second rule use the magic numbers

24 edges can be made 12 edges that can be made 6 edges that can be made 3 edges.

You have your gun barrel or oil drum and three levels of LOD

Third make it more than what you think you need with the ideal that it’s easier to make less out of two much that it is to make more out of not enough. I can LOD a high poly model faster than I can add detail to somehting that looks like it’s been hit with a 20 pound sledgehammer.

The reason, in my opinion as to why there is no true numbers as it use to be about what you could fit on a CD than it was about hitting the number that would decay the performance of the game. Now counts as to performance are not that fragile and I would be more worried about the total number of draw calls as to texture as I would as to the number of polygons that fits the design.

Proof of concept.

https://www.youtube.com/watch?v=IQ_BWblteQU

Great points and much more concise than my long wall-o-text. :slight_smile: