Topics

1

General / New GPU to improve speed or useless

« on: February 24, 2014, 04:09:25 PM »

Hi,

I'm currently looking about improving the photoscan process by giving a boost to my computer. I don't want to change my workstation since it's a 6 months old one...

Right now, I have a i7 4770L + GTX780 and 32 Gb of RAM.

I found in an old thread (dec 2010...) that the GPU was used only on the geometry building stage, but not in camera alignment, dense cloud and texture creation.
Then if the GPU is still used for only the geometry stage, I may prefer spending some money in a new lens or an extra DSLR, but if the GPU is used and in almost or all the steps, perhaps it's worth buying a second GPU.

And about the CPU, if I disable a total of 4 cores in the preferences (2 per card since my hyper threading is enable), how things are working? only 4 physical cores will be use and not the HT ones? or it's an "unknown"?

Thanks!

Does someone have the info?

2

Face and Body Scanning / improving quality on shooting time + questions

« on: February 18, 2014, 05:04:48 PM »

Hi,

I have several technical questions in relation to the shooting. I'll have to shoot people with just one DSLR (5D MkIII) and doing head scan and body scan. Of course I know that doing a scan with just one DSLR won't produce the best scan ever, but i already have good results, then for that, it's ok.

1 - In the documentation, it's mentioned that fixed focal lenses are advised. Is using a zoom lens (24-70mm) fixed at 50mm will be problematic? Even if it have some micro variations of zooming while shooting, between two photos?

2 - What is the best focal lens to provide good quality? 50mm 85mm? (on a full frame camera).

3 - What is the best compromise in terms of scan quality: increasing the ISO to increase the depth of field or lowering as much as possible the ISO even if it reduce the depth of field? Because I'll shoot outside, I won't be able to use studio lights. Of course, I would like to have a decent shutter speed.

4 - To improve the alignment of the photos, then the dense cloud generation (and reduce as much as possible the noise) in the final model, is it better to do a set of photos which will include the whole model in each photo for a first pass, then in a second pass, doing close up, or only close up are enough? Having these photos taken far from the model may introduce some extra noise?
I'm considering doing my scans in several pass in fact, like the full body in low quality, then shooting separately the face/head, the hands, parts of the body, then when doing, processing the scans separately, then at the end, recombining everything in one mesh in ZBrush. It may be a longer process, but perhaps can increase the quality of scans taken in not very good conditions?

5 - in addition to above, is it better to do in several chunks a scan by far and a scan with closeup photos and then combining them or just having all the photos, far and close, in the same chunk?

6. The Ultra high quality of dense cloud worth the extra waiting time in terms of quality (at least for a face/head) or high is far enough? I mean if adding 10 extra hours of computing versus 10 hours (or less) of 3D retouching in ZBrush.

7. no problems on shooting photos with two different focal lens? (35mm for photos by far and 85mm for closeup)

Thank you for your help!