Texture Resolution VS Texture File Size

[Anonymous]

Hi 

Just wondering what effects rendertime, Ram, etc more - the filesize of my bitmap or the resolution ? 

So is it faster with an a 8k texture thats olny 1MB big or an 2k texture thats 10MB big.

So will the filesize affect my memory more than a big texture resolution ?

Thanks,

Rob

[irishman_team_kilber]

it will depends how much ram you have inside your computer, the more things you have in your scene lights models, animation camera sfx etc all have to be calculated  and then rendered, the longer it will take to render, if you have a small scene with a few objects the unless time it will take to render your scene.

everything effect memory the more stuff you have on your computer's hard drive the unless memory you will have to use, everything you install uses up memory sorry if this sound condescending

[Anonymous]

Thanks, but i meant in general: Does it depend more on the filesize or on the resolution of the texture ?

[RGhost77]

@Anonymous You talk about different image formats, without or with MIPmap?

[Anonymous]

Without MIPmap.

I am talking more about png, tifs, or any other uncompressed format.

So i have the same texture twice: 

First one    :  PNG (4000x4000px) - Filesize is 1MB

Second on :  PNG (500x500px)     - Filesize is 10MB

Which one will load, render faster? Which one will consume less RAM? 

So is it possible to gerneralize it to something like "Big resolutions do not matter as long as the filesize is small" ?

[CAMedeck]

From what I understand, it is mainly the resolution of the images being used as textures that will decide how much RAM you are using.  If you save a texture map as a JPG with high compression, the file size will be small.  But 3ds Max will need to decompress that image to use it.  So compressing an image file will not significantly reduce the amount of RAM needed by Max when applying that texture.

This is information I'd gleaned from forums over a decade ago, and have always assumed it to be true.  It makes sense to me, anyway.  I'd be interested to see if anyone else has another opinion or facts regarding texture map sizes.

[Anonymous]

Thats why i specified my question to PNGs, TIFFs. I know PNGs are not really uncompressed, but TIFFs are.

So lets just look at TIFFS to specifie my question even more:

First one    :  TIFF (4000x4000px) - Filesize is 1MB

Second on :  TIFF (500x500px)     - Filesize is 10MB

Which one will load, render faster? Which one will consume less RAM? 

Is it now possible to gerneralize it to something like "Big resolutions do not matter as long as the filesize is small" ?

[Anonymous]

Thats why i specified my question to PNGS, TIFFS. I know PNGS are not really uncompressed, but TIFFS ar.

So lets specify my question even more:

First one    :  TIFF (4000x4000px) - Filesize is 1MB

Second on :  TIFF (500x500px)     - Filesize is 10MB

Which one will load, render faster? Which one will consume less RAM? 

Are high resolutions making a difference if the filesize is still small ?

[CAMedeck]

Are your numbers actual dimensions and file sizes, or are they arbitrary?

If you are not compressing an image, then the file size is directly related to the resolution.  The other factors would be the bit depth (how many bits per pixel) and other channels, like alpha.  Saving an Alpha channel will add to the size.  Reducing bit depth to 8-bit will reduce the file size, but also the quality.

I'm not sure if a 500x500 pixel TIFF could possibly be 10MB.  Or a 4k square TIFF be as low as 1MB.  I feel I can't give you much more of an answer without using some realistic data.  

[Anonymous]

Thanks for that, its getting clearer to me now.

I made these numbers up, but I was thinking about specific textures. I will have a look for them and post the actual dimensions or share a link so you can check them out.

[Anonymous · Accepted solution]

Hi @Anonymous,

As you might guess this depends on a lots of other parameters concerning both software/hardware setup.

Nevertheless If we ignore all the other less important variables. It all comes to storage access/transfer speed vs processing power (and to an extend RAM speed). There is not a rule of thumb about this but %90 of time a texture with smaller dimensions in pixel but greater files size is probably going to render faster than a texture with smaller file size but greater pixel dimension. (Unless you feed your textures to render engine through an abysmal storage device or network). 

That being said for a noticeable speed difference your scene must be reasonably texture heavy. You won't feel any difference between a teapot with a 4K tex@1MB vs 1K tex@10MB. Why? Because a 4K 8bit texture is 4096px X 4096px X 3 Byte/ (24bit total channel - without alpha) = ~50MB in RAM. to shade pixel (read:render) assuming we are talking about cpu rendering, cpu needs a 50 MB read from RAM (which is a trivial amount from CPU-RAM bandwidth point of view), than it needs to figure out what parts of that texture it is going to need (using UVW coordinates), do some filtering etc. if this whole process takes 0.08 seconds, and the 1024px x 1024px x 3Byte = ~3MB counterpart  takes, say, 0.04 seconds; resolution vs filesize won't matter that much in a 120 seconds render.

Other thing to consider is texture operations are not computationally heavy compared to say, other operations that needs lots of ray samples such as Monte Carlo GI, glossy reflections, area lights shadows etc . One might argue that all those rays gonna hit other textured objects which then will require texture operations to return a value, but still in those cases other calculations outweight the texure ones by far.

Still, in a nutshell, less pixel dimensions mean less work for cpu/ram thus it does almost always render faster. (but not much i'm afraid)

Of course this proposition applies in a situation where the following conditions are met:

1. All your scenes assets must fit in your RAM. (if not other less important variables that I mentioned above comes into play.)
2. You have an acceptable bandwidth to your textures assets in storage.

Best regards,

[RGhost77]

Also most of renders can shows statics how much time is needed to load and process bitmaps when rendering.