Curves drawn on photo fail to hit target in project despite correct Cplane method


I have traced a canvas tunnel in a photo, then oriented the image in perspective view to match, then saved the view, then did Cplane set to view, then saved that Cplane (Cplane05)

I select the trace I did, select project, select the surface dome (pale violet) hit enter

it says it missed, why ?

they align and Cplane is correct, created as soon as I had saved the matching view.

So if they align, and I save the view, and make Cplane for that view, and the grid looks square, why when that rectangle trace is projected to the dome does it manage to miss ?

I do it all again , still it misses target.

Just how do I trace something on a photo then orient the photo to match the dome, and project to the dome ?

I instead had to do a printscreen of this visible match, with a grid, and do a plotting,.
7 hrs work to get a simple shape onto my dome.

rhs dome project failure.3dm (992.6 KB)


Yep, that is what I mentioned yesterday - the projection will not be in perspective - if you change the view to a parallel projection you will see why that fails. I may have a tool someplace that projects in perspective, it might be worth a shot, I’ll try to find it.

@Steve1 - see how this works: (2.9 KB)

To use the Python script use RunPythonScript, or a macro:

_-RunPythonScript "Full path to py file inside double-quotes"

rhs dome project .3dm (978.2 KB)


Hi Pascal,
I , and anyone else, can line up an object to a photo in perspective view with a feature pretraced on the photo with curves, , run your python script.
It works, and the result matches the photo, as no change seems to occur until one moves the recipient surface and it separates from the curves on the photo. BINGO.

Prior to doing this now simple ProjectPerspective command, it took hours of fiddling, moving photo angle in top view, and its distance from the object, to get the object to match the photo.
It was more angle than distance as zoom does a bit of distance matching, though its too jumpy, almost there with one view, next move and a mismatch.


There is a BIG NEED here to enable the first stage to happen, to complemenet this and enable us all to make full use of this, to have a command called:-


run it, it says select source point on object, click my dome at its 12 oclock position, hit enter, it says select target on photo, I click top of dome on photo, hit enter, it then repeats all that for however many points it allows.
hit enter and the photo gets aligned to the object in perspective view. It allows for zooming in and out to make accurate point placements, (PerspectiveMatch doesnt allow that, and cant have curves grouped to the photo)

Sketchup prog did this, but didnt project any curves on the photo to surfaces. We need this in Rhino.

Then we can have a photo of something we are modelling, and bring some features from the photo onto the model to work with.

There are clients recreating things from photos, this will be a killer command, voted best command of the year :grin:

These two complementary commands WILL BE AWESOME. waited years for this. Honest !
So much unable to do , and what I wanted Rhino for, due to lack of this. I have friends also needing this.