How to tilt the plane of reconstruction to XY plane?

[Victor Ramamoorthy]

I just did a reconstruction using 48 images of an ornamental jewel box. The reconstruction dense point cloud is oriented on a tilted plane as shown in the attached image. How do I change the orientation to coincide with XY plane? Is there any other tool that can do that?

[Andrea Alessi]

Hello Victor,

you have a few options:

- in Pro and Aerial, you can eventually use control points (if available)

otherwise, in all versions you can use the following tools:




- up vector by two axis: the up vector is defined as the result of defining first the X and Y axis. Select the origin point (left click), then a point to define X axis with another left click (origin -> X) and then another left click to define the Y axis ( origin -> Y). The resulting axis is automatically computed.

- up vector by plane: (personally my favorite ) - define the ground plane by selecting three points (in your case, the floor or the top of the box, for example).

- up vector by two points: select the up vector by clicking the two points that would define it (in your case, the wall)

- use the gizmo to manually rotate all structured items: use the rotation tool or input the transformation manually

[Victor Ramamoorthy]

Wow! I am very impressed! Thanks Andrea for explaining this neat trick. I have two other questions:

1. Is there a scripting tool that would enable me to read image files in a folder, create dense clouds, and store the point cloud in another directory, for example in ..obj format?

2. Is there a nice way to segment the reconstructed object and the floor plane point cloud so that the reconstructed object can be stored without any intervention from the user?

I am trying to create a pipeline using Zephyr as a front end processor and my matlab code to post process. Any help is really appreciated.

After struggling with matlab photogrammetry scripts, I really admire what you have accomplished. Wonderful contribution!

[Victor Ramamoorthy]

Hi Andrea, I tried your up vector by plane method. It did not work. I don't know what I am missing. Can you help?

[Andrea Alessi]

[Victor Ramamoorthy]

Hi Andrea,

One thing that I did not do is mesh generation and texture mapping. May be that without mesh generation, the normal is not defined and dot and cross products required for axis of rotation may be resulting in nothing. Let me know if I am on the right track or guessing wildly! I also noticed that when I tried to pick points on the planes, the picked points did not show up with different color. Please help. Thanks.

[Andrea Alessi]

Hi Victor,

you can use those tools just after the sparse point cloud generation.

What do you mean they do not change color? You shold simply see a triangle appear as you click.

You will need only 4 clicks in order to define the up vector with the triangle tool:

[Victor Ramamoorthy]

I created mesh and texture. Still it does not align with XY plane. When I click on the up vector by plane button, the cursor turns into a +. But nothing happens.

[Andrea Alessi]

You will need to click with the left mouse button on the desired ground plane.

Can you record a video in case you are still having issues? thanks!

[Victor Ramamoorthy]

While trying to do the alignment to XY plane, Zephyr crashed and I have sent the dump to you.

[Andrea Alessi]

Ow that's very odd, thanks for sending the dump! I think there is something odd at play here. We'll look at the dump, thanks!

[Victor Ramamoorthy]

I got it working finally! I selected the points clockwise and hence the alignment is inverted. I should have selected the points on the top of the box anticlockwise.

[Victor Ramamoorthy]

Thanks for your patience Andrea. I now need help with scripting!!

[Filippo]

Thanks for your feedback Victor!

We are planning to revise the user interface for the alignment tools to make them more user friendly.