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rajesh_nest

OpenGL 10 million triangles in OpenGL

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I need to load and view a mesh having 10 million triangles in OpenGL.
(Are there any limits for size in OpenGL.)

I also need to render the large mesh with an impressive frame rates (say 25 frames/second).

So What are the optimizations strategies, I need to consider, for loading and rendering the large mesh?

[Edited by - rajesh_nest on July 6, 2010 12:11:23 PM]

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Any limits are in your graphic card && RAM.
About loading: to speed up it u have to chose good format
About rendering: read about VBO+VAO and texture albums

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Quote:
Original post by furrymaster
Any limits are in your graphic card && RAM.



I am using NVIDIA GeForce GTX 260 (Video Memory 896MB) as the Graphics Card.
and my System RAM is 4GB.

Quote:
Original post by furrymaster
About loading: to speed up it u have to chose good format


Which format should I choose to speed up?

Quote:
Original post by furrymaster

About rendering: read about VBO+VAO and texture albums

I am already using VBO.(only VBO,not VAO).

I am not using texture albums. BTW What is texture albums?


But I am not able to load mesh with 10 million triangles.

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10 million faces aren't that much. There won't be any problems on modern GPUs.

Quote:
Original post by rajesh_nest
Which format should I choose to speed up?

Depends entirely on what type of per-vertex data you need.

Quote:

I am not using texture albums. BTW What is texture albums?

He means a texture atlas. And they aren't really needed unless you have a very large number of small textures (eg. if lightmapping).

Quote:
Original post by rajesh_nest
But I am not able to load mesh with 10 million triangles.

Why ?

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Quote:
Original post by rajesh_nest
So What are the optimizations strategies, I need to consider, for loading and rendering the large mesh?


Do you actually have a 10 mil triangle model, or are you just speculating?

If you do, then what file format is this 10 mil triangle model stored in?
And how large (in MBs) is this file?

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Quote:
Original post by samster581
Quote:
Original post by rajesh_nest
So What are the optimizations strategies, I need to consider, for loading and rendering the large mesh?


Do you actually have a 10 mil triangle model, or are you just speculating?

If you do, then what file format is this 10 mil triangle model stored in?
And how large (in MBs) is this file?


http://graphics.stanford.edu/data/3Dscanrep/

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Quote:
Original post by samster581
Do you actually have a 10 mil triangle model, or are you just speculating?

If you do, then what file format is this 10 mil triangle model stored in?
And how large (in MBs) is this file?



Yes I do have and size of the file is approximately 400MB (My actual triangle count is 40 million triangles).

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Quote:
Original post by rajesh_nest
Yes I do have and size of the file is approximately 400MB (My actual triangle count is 40 million triangles).

File format??

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Quote:
(My actual triangle count is 40 million triangles).

you can expect your GPU to push about 400MTriangles/s, your peak fps would be 10Hz with brute force rendering.
you will have to consider other optimization
-Level of detail
-clusterting the mesh into smaller chunks + occlusion queries.
-optimized index lists for various views.

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This is a method credit to Martin Rystrand when at Massive Entertainment 1) Take the camera position 2) Find the scene voxel given that position 3) Get the possible visible set of triangles from that voxel Now how to build the possibly visible set? i) Place a camera in the center of each voxel. Raster with a z buffer on each triangle in the model with a flat (no light) model such that each triangle can be identified with its color. With rgb you can have up to 16 million triangles but with also using the alpha channel you can have up to 4 billion. ii) For the 6 sides of each voxel rasterize as above and put all visible triangles (collected from the pixel colors) in a list of indices (you could RLE encode it for example) Et voila! Possible visible voxel set for the win! Cheers,

 

Quote:Original post by rajesh_nest

Yes I do have and size of the file is approximately 400MB (My actual triangle count is 40 million triangles).

Edited by jbadams
Restored post contents from history.

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