Getting Scale Correct in Standard Version

[AndyVirt]

Hi All, have just created my first dense point cloud then mesh of a building from drone - looks fantastic.  The point cloud scale is correct but the OBJ file is about a third of the size (incorrect).

Now i understand that if i'd bought Pro i could have added scale bars (i do know the measurements of this building).

Couple of questions:

Why is the point cloud perfectly to scale and not the mesh?

Is there anything I can do to get the scale correct on the OBJ file in Standard version?

Many thanks!

[AndyVirt]

Just a quick follow up:

If the dense point cloud is to scale every time, why would the mesh not be?  Does the software do this deliberately?

Still looking for a solution / workaround, if possible.

If there is no solution to this, please let me know - i need to know if the Standard version doesn't meet my requirements.

Many thanks.

[James]

As far as i know, in standard version there is no way to have any fine control over the scale of anything, but all elements (mesh, clouds etc) should be the same scale as each other.

How are you determining what is the right scale and what is not, and can you post some examples/screenshots?

[AndyVirt]

Hi James, thanks for responding.

OK, the files i have wouldn't really count as a good test now i've looked at them.

I have 1 set of photos and have then produced dense point clouds and meshes using different settings (and cropped things).

But...  having now looked at the results, one point cloud (which was hardly cropped) shows the building at 20ft high, the other point cloud (cropped) has it much smaller - i now can't remember the settings for producing those 2 point clouds so it isn't a good test.

So, could someone confirm that those measurements were pure estimates?

If i produce a point cloud or mesh from these same photographs many times, could the measurements be different each time?

That first point cloud was the one i thought was accurate (these measurements of the building are online and the software i view them in has a measuring feature) but it isn't quite as accurate as i first thought.

[Alexey Pasumansky]

Hello AndyVirt,

All you can do in the Standard edition to get some kind of rough manual scaling it the following:
- in the Preferences -> Appearance -> Model view section set Grid -> Cell Size to N meters,
- in the Model Menu -> Show/Hide Items section enable Show Grid option,
- switch to Orthographic view mode via Model Menu -> View Mode,
- and finally use Scale Object tool (also from the Model Menu or a Toolbar) in order to adjust the model size to the grid cells.

Without that the default object dimensions would have an arbitrary scale after each camera alignment.

There shouldn't be any difference in the point cloud and mesh model dimensions produced from the same project and it's strange that you are observing that. If you can reproduce it on a small project, could you please send it to support@agisoft com: a project that contains camera alignment, tie points, dense cloud and mesh (saved in PSZ format) and the exported point cloud and mesh that you are comparing in the external application.

[AndyVirt]

Thanks very much for your help James and Alexey, i'll spend some more time looking at this.

[Kiesel]

Hi AndyVirt,

perhaps this is also of some help:

https://www.agisoft.com/forum/index.php?topic=8677.msg41310#msg41310