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Author Topic: Two noob questions  (Read 6266 times)

rbnkc

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Two noob questions
« on: June 07, 2016, 09:07:45 PM »
Just starting out with detailed modeling:

1. When I load and align my images they are inevitably grossly skewed/rotated from the trackball/local coordinate system. Its easy enough to translate the model to center on the trackball but I haven't figured how to align the trackball axis with the preferred model axis. What am I missing?

2. For photo alignment, I want to use all the capture points in the images. Once a preliminary model is created I want to use it to create a mask and use that mask to regenerate (hopefully) a better dense point cloud. There is a button for using or not using masks on the photo alignment but there is no equivalent switch on the dense cloud generation. Does the program assume that if masks exist then it will use them?

Thanks

Alexey Pasumansky

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Re: Two noob questions
« Reply #1 on: June 07, 2016, 09:09:31 PM »
Hello rbnkc,

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

Masks are applied automatically for Dense Cloud and Texture generation, if present.
Best regards,
Alexey Pasumansky,
Agisoft LLC

rbnkc

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Re: Two noob questions
« Reply #2 on: June 07, 2016, 09:29:06 PM »
Thanks Alexy,

 I understand that I can rotate the object relative to the screen but the trackball rotates as well and remains at its original orientation to the scanned object. It can be inconvenient when editing the mesh or deleting points because a vertical or horizontal rotation of the object to say get it level to the screen may require individual adjustments on all three axis of the track ball that is neither lined up with the object or the screen and then still not be very precise.

What would be nice is to be able to align the object with the screen then press a button that would also align the trackball to the screen. Then local x,y, and z axis would be in alignment.

That's probably a lot easier said than done though.

and thank you for the confirmation on the masks

JulieLov

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Re: Two noob questions
« Reply #3 on: June 08, 2016, 02:00:56 AM »
Hi,

I also have two noob questions as I'm just beginning to learn this software.

1. My chunk report shows max reprojection error as 0.493343 (38.8001pix). Can you please explain what units the 0.493343 are? This report was produced by right clicking the images chunk and hitting 'show info...'. I attached a picture of the report in case you needed to see it.

2. In the Cameras Reference tab, error is reported in (pix) following my projections column. However, I don't believe this is reprojection error as the maximum value is well below the 38.8001pix from above. Can you please explain what this error is?

Thanks!
Julie


James

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Re: Two noob questions
« Reply #4 on: June 08, 2016, 12:34:15 PM »
You can use Rotate Object tool for unrefrenced chunks to change their orientation in the coordinate system.

shown in the attached image, it does do what you want it to do!

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.

rbnkc

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Re: Two noob questions
« Reply #5 on: June 08, 2016, 08:19:29 PM »
Thank you James,

That does exactly what I needed. It was the three step process and using the space bar to "set " the new orientation that I was missing. Life just became much easier

pch90265

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Re: Two noob questions
« Reply #6 on: June 09, 2016, 10:38:22 AM »
This is a TREMENDOUSLY helpful post for me, as well!!!  Awesome sauce.

Steve003

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Re: Two noob questions
« Reply #7 on: October 12, 2021, 05:51:09 PM »
Hi,
Those steps are essential, BUT THERE IS NO GRID TO ALIGN TO , one needs a grid.

How is the grid shown up as my grid button is already 'depressed' and the screen has none.

I had to move it (object)  to screen edge to get an idea, which cannot be right, we need a grid, but then to tumble the model in perspective mode, rotateObject seems to be the tool, it tumbles ,BUT then 7 or 1 or 3 and they are all out of alignment again.

So , after this ortho method , how does one tumble the object about in perspective ?
the ball tumbles the box not the object.

metashape 1.7.4 in use.

Steve