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Old 19th May 2007, 10:40 PM   #1
starship winger
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Question large size?

i wonder what if i make model starship large size on screen like 10x10 or 300x 300? it will cause low memory for large size or nothing happen? let me know thanks...
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Old 20th May 2007, 06:20 AM   #2
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Default Re: large size?

Hi making your model larger, will increase the amount of memory used, and will slow your computer down in respective of how little memory is available and graphics card speed and memory. if you have system memory of 2gigs and a fast graphics card with 1 gig then it would not slow it down too much. Hope this helps.

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Old 20th May 2007, 09:03 PM   #3
starship winger
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Default Re: large size?

i see, hmmm better 50x50 or less? what size you use more often?
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Old 20th May 2007, 11:04 PM   #4
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Default Re: large size?

I dont think the size of the model will have anything to say. Its how many objects and how many polys on screen that will have an impact on the memory. Resizing wont help you. 1000 objects and 2 millions polys wont use less memory if its 50x50 instead of 300x300.
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Old 21st May 2007, 02:09 PM   #5
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Default Re: large size?

Quote:
Originally Posted by tbd View Post
I dont think the size of the model will have anything to say. Its how many objects and how many polys on screen that will have an impact on the memory. Resizing wont help you. 1000 objects and 2 millions polys wont use less memory if its 50x50 instead of 300x300.
..... Agreed.
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Old 21st May 2007, 07:49 PM   #6
lisa
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Default Re: large size?

Correct.

The physical size of the model shouldn't effect the memory usage, but the poly count will.

However, exceptionally large and exceptionally small models are sometimes difficult to work with for other reasons. If your model is too large, your graphics hardware may not have enough z-buffer precision, and you'll experience z-fighting\flimmering. This is not an AC3D-specific issue; it's just the nature of 3D hardware. Small objects can make the camera difficult to work with.

A common trick most game and movie studios use is to break very large models up into multiple pieces, and then only assemble them or use a low-lod (reduced level-of-detail) or "imposter" model when the entire object must be in the shot. This also allows different artists to work on different parts of the model at the same time.
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Old 23rd May 2007, 09:33 AM   #7
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Default Re: large size?

Sounds like you know what you are talking about lisa, cos I dont
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Old 23rd May 2007, 12:13 PM   #8
lisa
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Default Re: large size?

LOL.

I do 3D stuff for a living. Technically, I'm a programmer, not an artist, but I like to play around with the art side, too. :-)
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Old 23rd May 2007, 12:20 PM   #9
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Default Re: large size?

Quote:
The physical size of the model shouldn't effect the memory usage, but the poly count will.
imho the amout of triangles is only one factor...
  • Different display methods(wireframe only, solid...)
  • Use of textures
  • Texture size
  • Amount of triangles, and how many of them share vertices
  • Display size, the bigger the more pixels have to be calculated
  • anisotropic filtering, antialias n such stuff
EDIT: um sorry forget about it, i thought u were talking about FPS

Last edited by little_penguin; 24th May 2007 at 02:33 PM.
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Old 23rd May 2007, 04:34 PM   #10
lisa
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Default Re: large size?

- Different display methods(wireframe only, solid...)

This effect frame rate--often significantly--but generally not memory consumption.

- Use of textures
- Texture size

Textures are usually the number one source of memory consumption in any 3D application. Textures often consume more memory than the geometry, especially in modern applications that use many different types of maps on a single model. (i.e. diffuse, specular, normal, etc.)

- Amount of triangles, and how many of them share vertices

This is polycount. Number of shared vertices matters, but not as much as other factors.

- Display size, the bigger the more pixels have to be calculated

Again, this effects frame rate, but not memory per-se unless frame buffer calculations are done in software instead of hardware. Possible, but not common these days.

Note: by memory, I mean "main memory", aka RAM. A large frame buffer does of course effect video memory, often significantly, as it increases both the visible buffer as well as the back buffer, stencil buffer and z-buffer.

- anisotropic filtering, antialias n such stuff

Again, unless this is being done in software on the CPU, these will effect frame rate but not (main) memory consumption. Whether or not they effect video memory usage is dependent on the algorithims used.

Technically, while anisotropic filtering is very GPU intensive, and may use more video memory *bandwidth*, total consumption can actually often be reduced becase the better filtering means lower-resolution textures can be used.
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