Slow reconstruction

**cam3d** · 2026-10-13, 04:58 AM

Hey MPP33 -

Here are my thoughts:

- A 10 year old 4GB VRAM GPU is considered very weak, and for serious 3D production work, close to unusable. The RTX2000 is 16GB VRAM and much more powerful and suitable for this kind of work.

- 32GB RAM is at the low end of the spec scale with oversaturated RAM you will end up with a SWAP slowdown - Best to upgrade to 64GB if possible to give yourself some processing headroom.

- As to this specific error, I'm not sure, but it could be a CUDA compatibility issue with your old GPU. The provided log seems to be truncated. Can you please provide the full session logs so we can do a proper analysis? Thanks!

If you want faster processing there are two primary options: Lower processing settings and/or better hardware - You will also get better at image budgeting, there is a sweet spot where you can take just enough photos for a good reconstruction, and excessive overshooting will slow down processing for very little gain.

**MPP33** · 2026-10-13, 05:51 AM

Hi,

thanks for the quick answer.
as mentioned, my feeling is that it worked better when I started to use Zehyr (with the same hardware).
Even bigger projects were started in the afternoon and next day I got the result.

And the fact that both hardware is showing the exact same error on the new laptop tells me it's not an issue on hardware side.

For the current step "computing photoconsistenvy" it seems to split it up in packages (1/10... 2/10...).
Old hardware needs 2h for one of this steps, new hardware is a bit faster 1h20min.
But again, both fully independent laptops are running this step on the CPU, both are not using the GPU at all.

For other steps it is using the GPU, so there is no general issue that the software isn't detecting it.

How do I export the full log? At the moment while in the process this is everything I can find and I can't export, just copy&paste. I think I have to wait until the process is finished?

Setting is "Urban" and "Normal", so not even highest quality as I experienced that "high" leads to worse results at least with "not ideal" pictures.

**MPP33** · 2026-10-13, 06:21 AM

New hardware is finished with the job and I`m quite happy with the result, just running creating the textured mesh and then I try to get the log files.

New observation:
During the step where it needs most of the time it doesn`t really use the RAM. Only 15GB of 32 are used at this step.
Only CPU is at the limit.

**Andrea Alessi** · 2026-10-13, 11:29 AM

Hi,

a few more comments building on what Cam has said:

from your log, I see you're running in OpenCL rather than on CUDA. OpenCL is still GPU accelerated, but it is slower than CUDA.

The reason why you're falling back to openCL rather than using Cuda are likely:

- Outdated drivers. Make sure you're running the latest drivers for your card. This should be enough to have your system run on CUDA again.

- Card no longer supported by NVIDIA - it's possible the latest drivers have phased out support for CUDA for your card. This can happen on older cards. If that's the case, you're either stuck with OpenCL, need to change card, or have to rollback to an older Zephyr version. As this card is almost 10 years old, make sure this isn't the case with the driver you're running.

The OpenCL error is not normal though, so either it's a driver issue that is also impacting OpenCL, or it could be hardware issue, or it could be a bug. Are you able to reproduce the issue or was that a "one time" occurrence? If it can be reproduced, In order to verify we'd need the .zep file (as well all the _files directory) and photos, if you can share them with us at support@3dflow.net - thank you!

**MPP33** · 2026-10-13, 10:06 PM

Hi,

It`s not a "one time occurance", it`s rather an "every time and on both hardware occurance"
Fully independend from the hardware the error is always there.
New hardware is just a bit faster (expected) but not dramatically different.

New hardware (company) doesn`t have the latest driver, but at this stage I don`t want to involve the IT department if not necessary.
Old hardware (private) got the latest driver yesterday and it seems that there is still full support for this GPU

Due to the size of the outcome I have tried to do make a "micro" project using only 2 pictures - thats the only way NOT to get the error and reconstruction is done in seconds.
When using 4 pictures the error is there again, my CPU fan could be used to dry hair and this certain task takes most of the time of the process.

By the way, it seems that I have to replace the GPU fan of my old laptop due to 2 nights of full power, doesn`t sound that good

E-mails you received:
1) both log files of the simplified main project on both hardware.
2) All Zephyr files and log file of the "4 picture project"
3) Pictures of the "4 picture project"
4) Log file of the "2 picture project"

**Andrea Alessi** · 2026-10-14, 12:18 PM

Thank you for sending the project file, logs and photos!

We were able to reproduce it on a similar-era Quadro - we'll be working on a fix and it'll likely be in the next patch!

**MPP33** · 2026-10-14, 10:31 PM

Perfect, thanks.
As always mentioned, it also happens with the modern (3 years old) NVIDIA RTX 2000 Ada

Looking forward to get a solution for this issue.

Slow reconstruction

Slow reconstruction

Comment

Comment

Comment

Comment

Comment

Comment

Comment