cleaning up interpolated mesh around roof line

[octopus]

Hi. I am making a model of a building from photos taken from ground.
It has a roof shape with ornaments that make unwanted dense cloud points
around the roof edge inside the sky. So, I removed them by masking the
sky portion in the photos, and selecting dense cloud points in the sky.

Now the problem I have is that generating mesh with interpolation enabled
still creates white area around the roof edge. Is there any way to
easily clean it up? The selection method by masked photos would be great
if it works also with mesh, but it seems to work only with dense cloud points.
I need to use interpolation for meshing since it works very well to
fill holes in many other locations in the model.

The image attached shows the cleaned up dense cloud (left), mesh with
interpolation (middle) and mesh without interpolation (right).

Thanks.

[ekbmuts]

octopus,  I get the same thing sometimes when shooting whitish objects against white.

I'm going to hazard a guess and say that the problem is exactly that:  white on white.  And, what's more, untextured white on untextured white.  So when Photoscan goes to make a depth calculation based on blur levels (if that's even how it does it - I actually don't know), it blurs white and everything on the roof of that building gets thrown into the same depth buffer as the sky as being at the same depth.  And hence, they sky is joined to your cows.

Is there any chance of getting up there and putting something of a different colour behind those cows?  Like a green screen?

Alternately, can you shoot on a cloudy/overcast day where there is at least some detail in the sky and it won't have the same basic colour as the cows?

Whatever you do, in my opinion you need to somehow create a separation between the cows and the sky so that they stop being connected

Jon

[octopus]

Hi ekbmuts;
 Thanks a lot for the suggestion.
 The white roof line against bright sun was one problem,
 but after making Dense Cloud, I was able to cleanup the
 unwanted points in the sky, by masking the sky in
 the photos and using the
  Tools>Dense Cloud>Select Points by Mask
 and just deleting those points. This tool is great.

 So, the Dense Cloud is pretty accurate, and if I mesh it without
 interpolation option, it produces a model of the roof edge
 without spilling into the sky. But if I mesh it with interpolation
 option, the roof edge spills back into the sky.

 I read in some other post that this is what interpolation
 option does for object edges, so I accept it. But I'd like
 to know if there is any way to easily remove these unwanted
 spilled portion of the mesh. Ideally, if I can select them
 by the same Points by Mask method (or Mesh by Mask)
 as Dense Cloud, but I do not find any tool like that.

 I wonder if any good method is available for such a situation.

[ekbmuts]

Yeah, I wonder too about that.

I wasn't aware of the usefulness of "Select points by mask."  I'll have to try that myself.  Tell me:  did you have to mask the sky tight against the roof line in order to get a good result.

Unfortunately, I don't think I can be of more assistance on this point.  Maybe one of the Photoscan veterans will contribute to this because it would be god to be able to do that.

Thanks for the "Select points by mask" idea!

Jon