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Author Topic: Scale and orientation  (Read 15120 times)

ekbmuts

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Scale and orientation
« on: June 16, 2016, 12:51:04 AM »
I'm doing full body scans.

When I export my mesh and bring it into 3ds max, it's too small and not at 0,0,0.  Meaning, my original body was 6' tall but in 3ds max, it's 6 inches tall.  And it's upside down and not at 0,0,0.

What am I missing?

Jon

James

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Re: Scale and orientation
« Reply #1 on: June 16, 2016, 10:56:09 AM »
Use the below technique to orient your scans upright. To set a real world scale and/or specific location (such as 0,0,0) within photoscan you will need the pro version so that you can set markers/scalebars, otherwise you will have to do it externally.

You can use Rotate Object tool for unrefrenced chunks to change their orientation in the coordinate system.

My preferred method of using it is:

1. hit numpad 7 to go to top view
2. then invoke the rotate object tool to rotate the model to a top view.
3. hit space bar to return to 'normal' navigation mode
4. hit numpad 1 to go to front view
5. hit space again to return to rotate object mode and fine tune the rotation in front view
6. hit space to return to normal nav mode again
7. hit numpad 3 to get a side view
8. hit space to get back to rotate object mode and further fine tune the rotation if required
9. hit space to get back to normal navigation mode
10. hit numpad 7, 1 and 3 in sequence to check the model is aligned and repeat the above if necessary.

ekbmuts

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Re: Scale and orientation
« Reply #2 on: June 17, 2016, 12:43:42 AM »
James,  Great, thanks a lot. That's very helpful.

I do have the Pro version (actually a demo but I'm purchasing tomorrow) and I've just found in the help file something about markers and that.  Sounds like it would have been good to have a 2' long piece of wood in the photos so that I have a definite measurement tool.

I can probably fudge it and get pretty close.

Thanks again.

Alexey Pasumansky

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Re: Scale and orientation
« Reply #3 on: June 17, 2016, 09:53:14 AM »
Hello ekbmuts,

With Professional edition you can put several coded targets on the floor and measure their coordinates in the local system, that will allow oyu to have all the scans aligned and have the same scale, since the position of the targets wouldn't change, providing that they are not moved between the scans.
Best regards,
Alexey Pasumansky,
Agisoft LLC

ekbmuts

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Re: Scale and orientation
« Reply #4 on: June 18, 2016, 01:12:41 AM »
Alexey,  Okay. I think I'm tracking.

So let's say I put a number of colourful 1" diameter stickers on the floor around the model, for example.  Pink, red, green, whatever.  They might not be visible in every camera (some cameras are close-up on the head).

When I get my shots into Photoscan, I then put a marker on each of these different coloured spots in as many photos as they show up in (or does Photoscan get the idea after the first few and place markers itself?).

And then I tell Photoscan how far apart these markers are, having measured them on-site.  I'm not sure how to do that so perhaps you can point me to a page in the Help or something.

But overall, does that sound about right?

Jon

Alexey Pasumansky

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Re: Scale and orientation
« Reply #5 on: June 18, 2016, 05:56:19 PM »
Hello Jon,

I was thinking more about the coded targets that are sticked/glued to the studio floor so that their position doesn't change in between the shooting sessions. Also coded targets can be detected automatically by PhotoScan, thus minimizing the manual intervention.

But as a reference you can also use nice blog post by Lee: http://ir-ltd.net/delivering-aligned-and-scaled-photoscan-outputs/
Best regards,
Alexey Pasumansky,
Agisoft LLC

ekbmuts

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Re: Scale and orientation
« Reply #6 on: June 18, 2016, 09:32:11 PM »
Alexey,  Right.  I get it now.  Lee has them on his floor so I get what you're talking about. 

Thanks!

Jon