Define Distance not working as expected

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    Götz Echtenacher

    Hi John,

    thanks for this concise post! I didn't get the feeling you were ranting at all...  :-)

    Anyway, I can't see an error in your workflow and it seems to me it could be a bug.

    Since you have 3 points and it seems to me like you've established a horizontal plane, why not mathematically calculate the 3 coordinates of the points and use them as Ground Control Points? Because the you'd also cover the step of aligning the model to real space, something that doesn't work with a simple constraint of length.

    Selecting the Control Points in 3D view is actually a still fairly new introduction. Before, you had to do it in each image individually. This way has pros and cons (like everything) and many older users don't like the 3D placement very much. Also, the points that you then see in 2D images are only suggestions (black) that need to be confirmed by the operator (they turn blue once you grabbed them). The reason is that they are only estimations based on the current alignment and might be quite a bit off target. You don't need to confirm all of them, a handful from different angles is usually enough.

    Also, the "challenging" UI is something that has been criticised many times (also by me) and that for now just needs to be accepted. Once you get your head around it, it isn't that difficult. Most software has it's own logic, RC is just a bit more different than most.  ;-)

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    Rafa CR

    Hello John, 

    Do you enter all information manually or you use define distance tool in alignment tab ? 


    If you click on define distance tool and then on 3d window you can mark each point or create new ones (to do so drag the mouse from one to another point) then type/define the distance and update registration. 

     

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    John Shulters

    Thanks for the comments so far! I took some time to go through the workflow again with this set of photos (since they are very clear and producing good scan results). I imported the images, created 3 control points directly using the photos, then aligned the images. The results looked clean and showed my 3 control points correctly in 3D space. I click "Define Distance" and click-and-drag from point 0 to point 1. It returns a calculated distance of 18.56m. I type 4.7 into the defined distance area and click update and receive the same error as before..."Updating Constraints (draft): Operation failed. No component with valid ground control constraints found." Is "Update" not the thing I should be clicking to change this value? The error does not make sense to me. It sure seems like I'm just clicking something incorrectly or doing things in the wrong order, because everything seems to be working perfectly until I try to update the calculated distance with the correct one. Any help here would be greatly appreciated!

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    Götz Echtenacher

    Hi John,

    I just tried it on a model of mine and it works without your error message. However, after using Update, the old distance is still active. BUT my distances are not actually updated and remain the same as before. Maybe there's a bug? 

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    Rafa CR

    Hi John, 
    I have tested all functions of defining distance, and all seems to work properly. 
    Please check your control points if they are added correctly. 

    Götz 
    if you change the value and immediately click Update old value will remain. This is already reported Bug - when you type values in settings you have to confirm them with enter key otherwise RC want take in to account. 

     

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    Götz Echtenacher

    Ok, I've managed to recreate the error.

    It comes up when I define the CPs only in the 3D window without actually confirming them in the images.

    What is weird is that John's first screenshot shows them being properly defined, so it seem like that's not the issue.

    Rafa, thanks for the suggestion but I already do that. The measurement stubbornly stays the same, never mind how often I update:

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    Götz Echtenacher

    Whoa, now I get the same error as well!

    Just played around a bit and all of a sudden it was there.

    I think it first started when I wanted to update a model where there was a distance without any assigned points.

    From then on nothing worked anymore.

    Now it get's realy weird: I started the project new, and this time it NEVER worked. Then I started it again an voila, everything works as it should and I can play around and nothing can cause the error to pop up.

    In my view that clearly points to some inconsistency and therefore a bug.

    So John, I suggest you try and restart your project a couple of times and see if that works.

    The updated distance is still different from my input though...

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    John Shulters

    Well, I reopened the same file I was working on yesterday (that gave me the error). I re-typed 4.7 into the defined distance field, this timing hitting enter on the keyboard instead of the number pad, clicked update, and it worked. Strange. It is showing a distance of 4.75m instead of 4.70 which I specified, but still close enough for what I need. I'll keep this workflow moving forward and hope it continues to work as expected. Thanks for all your input.

    BTW, I know there may be others out there that are struggling with this scaling and alignment workflow, and I know for me it would have been useful to watch a video of the process in action. I'll see if I can put one together and I'll share a link here when I do, but folks (including me) might like to see an official how-to video from the RC team. Thanks!

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    Götz Echtenacher

    Hi John,

    indeed very strange. In my eyes even worth a bug report. But maybe the guys will move it if they agree?

    It really should be 4,70 exactly since this is the only constraint and therefore nothing else to counteract this measurement.

    Does it improve if you add the remainig 2 distances?

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    Rafa CR

    Hello John, 

    Would be possible for you to share your project files that we check the issue?


    Thank you 

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