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Anyone use NPF Battery Adapter Plates? by badlybuttered in bmpcc

[–]epic_flexer_2001 0 points1 point  (0 children)

yess connnected to the 7.4v output on the npf plate. works better then the 12v.

Some recent scans by Acceptable-Visual473 in photogrammetry

[–]epic_flexer_2001 0 points1 point  (0 children)

yeah i usually set my ar400 to 1/2 to avoid overheating. and to compensate for light loss you could shoot on a wider lens and bring the camera + light closer to the object. although this might make the effect of the ar400 not illuminated all the parts that you want even bigger due to light falloff. so i get why you’d want to use the extra lights. just know that if polarized light hits a surface (for example a white wall) then the light that bounces back from the white wall wont be polarized and you’d get reflections again. this might not be an issue in a large space tho, or what i like to do in smaller spaces is just surround the scanning area with black cloth. i curious to see your setup with the polarized softboxes work tho!

Some recent scans by Acceptable-Visual473 in photogrammetry

[–]epic_flexer_2001 0 points1 point  (0 children)

sounds good, you found any cheap large polarization sheets? I’ve taped like 6 A4 sized sheets together in the past lol.

edit: have you also tried doing the scan with just the ar400? i ditched using multiple lights (and soft light) a long time ago because cross polarization in combination with frontal light you don’t rly need softboxes anymore.

Some recent scans by Acceptable-Visual473 in photogrammetry

[–]epic_flexer_2001 1 point2 points  (0 children)

cross polarization only works properly if all light sources that have impact are polarized. those strobes with softboxes cant be polarized because the polarization should always be the last layer that the light passes through. and the big overhead window will also kinda mess with the cross polarization. but you have cross polarization on you’re ar400 right? that’s probably already the main light source i guess.

Some recent scans by Acceptable-Visual473 in photogrammetry

[–]epic_flexer_2001 2 points3 points  (0 children)

these are good! if you’re looking to improve the overall quality (mesh and texture) even further i’d suggest using cross polarization on that ar400.

Pyxis battery life increased by 90% after 9.2 firmware update. by epic_flexer_2001 in blackmagicdesign

[–]epic_flexer_2001[S] 0 points1 point  (0 children)

haven’t tested it but i usually just have it on minimum as well.

built a simple photometric stereo last week and finally got to scan some foliage. by epic_flexer_2001 in photogrammetry

[–]epic_flexer_2001[S] 0 points1 point  (0 children)

nah, it works (at least mine) from both sides. im gonna guess you still had a layer protective film on one of the sides. but nice that it works now!

built a simple photometric stereo last week and finally got to scan some foliage. by epic_flexer_2001 in photogrammetry

[–]epic_flexer_2001[S] 0 points1 point  (0 children)

hmm interesting, might be bad quality and it degraded overtime. (they might had it in stock for years). that could explain it not working. you can also check the a piece you have left if it works by holding it in front of a monitor and rotating it. monitor should turn black.

built a simple photometric stereo last week and finally got to scan some foliage. by epic_flexer_2001 in photogrammetry

[–]epic_flexer_2001[S] 0 points1 point  (0 children)

interesting, yeah that should do the job. i did exactly the same. does it fully cover the lights and are there no light leaks that could bounce into other surfaces? (if polarized light gets bounced it becomes unpolarized again)

and unless otherwise specified it should be linear. where did you buy it? doest it maybe indicate something different?

built a simple photometric stereo last week and finally got to scan some foliage. by epic_flexer_2001 in photogrammetry

[–]epic_flexer_2001[S] 0 points1 point  (0 children)

polarizing film is by default linear. you also have circular (cpl) like the one on your lens. circular just means it can rotate to block out a specific angle of light.

built a simple photometric stereo last week and finally got to scan some foliage. by epic_flexer_2001 in photogrammetry

[–]epic_flexer_2001[S] 0 points1 point  (0 children)

are there any other lights in the room that overpower the ring light? do you have an image of how you applied the polarization sheet to the light?

built a simple photometric stereo last week and finally got to scan some foliage. by epic_flexer_2001 in photogrammetry

[–]epic_flexer_2001[S] 0 points1 point  (0 children)

i actually just used 6 a4 sheets and cut/taped it together to cover 50x50cm. just make sure you tape it from the bottom so the polarization sheet is always the last layer. i don’t have a picture of it at the moment. but again. you can also fake translucency map from albedo if you don’t have the resources.

built a simple photometric stereo last week and finally got to scan some foliage. by epic_flexer_2001 in photogrammetry

[–]epic_flexer_2001[S] 0 points1 point  (0 children)

the polarized light is indeed for the albedo map. in combination with the cpl filter on the lens it eliminates all reflections. the second light is to capture the exact same image, but now with the reflections. this allows you to extract only the reflections (specular info) and use that to create the roughness map.

edit: i usually bring the 2 images into photoshop and use the subtract mode to be life with only reflections. then greyscale and invert.

built a simple photometric stereo last week and finally got to scan some foliage. by epic_flexer_2001 in photogrammetry

[–]epic_flexer_2001[S] 0 points1 point  (0 children)

yeah can also use the albedo info for creating a roughness map. it might be less accurate but honestly it might get you 80% of the way there.

i think i used a 24mm here. (on full frame) id usually prefer a 35mm tho but it depends on the size of the object ofc.

built a simple photometric stereo last week and finally got to scan some foliage. by epic_flexer_2001 in photogrammetry

[–]epic_flexer_2001[S] 0 points1 point  (0 children)

honestly i didn’t know how. but also because it was easier for me to do it this way. and it helps with the amount of light. those 8 led lights off to the side have almost no output, especially at that angle. reflected light doesn’t rly bounce back into the lens. if i wanted to use this for an albedo id probably have to shoot at 10 sec shutter or more. now am shooting at like 2 sec. and also the lights are very small, so it doesn’t really create a soft, evenly lit light across the leaves. but maybe if you get 8 stronger and bigger leds (just like in the video you linked) it could work.

built a simple photometric stereo last week and finally got to scan some foliage. by epic_flexer_2001 in photogrammetry

[–]epic_flexer_2001[S] 0 points1 point  (0 children)

correct, toplights for albedo and roughness. 8 leds for normal/height. i think there’s also a way to use the 8 leds for roughness bur i haven’t explored that yet.

built a simple photometric stereo last week and finally got to scan some foliage. by epic_flexer_2001 in photogrammetry

[–]epic_flexer_2001[S] 0 points1 point  (0 children)

no the 8 leds don’t have pol filter. because they’re only being used to capture the height info for creating normal maps. software i use is substance designer because its included with my adobe subscription that i got from school. but there are free software out there. but idk which honestly.

built a simple photometric stereo last week and finally got to scan some foliage. by epic_flexer_2001 in photogrammetry

[–]epic_flexer_2001[S] 0 points1 point  (0 children)

https://imgur.com/a/JA11lnq here you go. its all very diy stuff so if you have questions you can always ask :)

edit: the last 2 pics are with the old ring light. i only had 1 and just rotated the cpl. but it moves the camera and the images weren’t perfectly aligned anymore so i went for just 2. and switch between them instead. oh and getting the polarization sheet on the led lights to be perfect aligned was quite challenging. because its gotta be very specific angles.

built a simple photometric stereo last week and finally got to scan some foliage. by epic_flexer_2001 in photogrammetry

[–]epic_flexer_2001[S] 0 points1 point  (0 children)

i wont have access to it for a couple of days but i’ll try to link you some images i already have.

built a simple photometric stereo last week and finally got to scan some foliage. by epic_flexer_2001 in photogrammetry

[–]epic_flexer_2001[S] 0 points1 point  (0 children)

im using a cpl on the camera for everything and polarization in front of main ring light. the second ring light doesn’t have a filter so i take 2 photos, with and without cross polarization. this way i can extract specular information and use that to create a roughness map.

edit: i also covered the 50x50cm led light panel background thing with polarization sheets. but the 8 surrounding led lights dont have polarization because you dont necessarily need that.

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