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Author Topic: when is convenient refine mesh?  (Read 3965 times)

zagnimarco1

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when is convenient refine mesh?
« on: April 30, 2019, 10:23:51 PM »
Hi  i discovered a function  that i ignored for long time, "refine mesh"  i noticed  that can add a lot of details, but using in ultra high  settings is  very very slow, so my question is: is more convenient build a mesh in middle quality and then use refine mesh or  build in high or ultra high settings?If during refining  process the ram used is near to 100% it menas that i'm using disk swap and the process is slower?

Mak11

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Re: when is convenient refine mesh?
« Reply #1 on: April 30, 2019, 11:56:59 PM »
It really depends on the project. If it's a "simple" object scan or relatively small scan it's IMO best to generate the mesh in ultra-high from the get go. But for larger scenes it may help to generate mesh in medium or high and refine afterwards. But keep in mind that the refine mesh process relies heavily on the GPU's VRAM (the more you have the better because if it runs out of VRAM Metashape will use system RAM alongside it & this will totally trash your processing times).

Cheers

Mak

zagnimarco1

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Re: when is convenient refine mesh?
« Reply #2 on: May 01, 2019, 02:22:18 AM »
thank you Mak, i noticed a massive use of ram,but during the process seems to use the half of the  total amount of both  video cards

jenkinsm

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Re: when is convenient refine mesh?
« Reply #3 on: January 26, 2022, 11:33:55 PM »
It really depends on the project. If it's a "simple" object scan or relatively small scan it's IMO best to generate the mesh in ultra-high from the get go. But for larger scenes it may help to generate mesh in medium or high and refine afterwards. But keep in mind that the refine mesh process relies heavily on the GPU's VRAM (the more you have the better because if it runs out of VRAM Metashape will use system RAM alongside it & this will totally trash your processing times).

Cheers

Mak

Do you have any tips on how many photos (or megapixels) is the "limit" for a given amount of VRAM?

I have a very very large project that I am working on, and I am debating between generating a high-quality mesh and generating a low-quality mesh then refining. I am testing different approaches and the problem with the higher-quality meshes is that a lot of roadside objects and terrain do not end up in the final mesh, and the road itself tends to have more holes or really rough geometry. I like the overall quality and "completeness" that I get from Low or Medium-quality depth map-based meshes, but there are some fine details in the road that are not represented accurately (namely the cat eyes and rumble strip down the middle of the road, between the yellow lines.)

These details are important to me because the end result will be a drivable map for a VR driving simulator and the cat eyes/rumble strip provide a level of immersion that is not currently found in any of the tracks available online.

I noticed that the higher-quality meshes capture these details perfectly, but the low-quality mesh just has a rough approximation of these details and that's not enough for me. But the tradeoff is that the trees, fences, grass, etc alongside the road are more prevalent in the low-quality mesh. That's why I was thinking to generate using Low and then refine.

All that said, the test chunk I am working with has around 3,700 12 MP 16-bit TIFF photos and Refine Mesh is taking a crazy long time to do one iteration. I bet I've exceeded my VRAM limit (in spite of having 24 GB of VRAM on an RTX 3090). So, it might be worthwhile to break apart this chunk before refining each portion, but I don't know how small I should make each portion in order to not exceed my VRAM limit.

Any suggestions?

If Refine Mesh ends up being too time-consuming (and it sounds like it will), then I may take a hybrid approach where I generate the road mesh using ultra high quality and separately generate the surroundings using low quality. I would then decimate the road to my desired resolution. I don't know what problems I might run into here, so any advice is appreciated.

Thanks in advance!