Messages

1

General / Re: Cameras all inverted - flipped - upside down - relative to model

« on: April 07, 2025, 11:55:54 AM »

Hi!

Have you tried exporting the model as a different format?

Wish you all the best!

2

General / Re: Can i mix vertical and horizontal pictures in one scan...?

« on: April 07, 2025, 11:53:02 AM »

Hi JohnyJoe,

from my experience, Agisoft has no issue aligning nadir and oblique images from one chunk, even though it gives a warning if you really want to add the oblique images.
It might be different for completely horizontal images.
It should also work with different focal lengths

3

General / Re: markers not appearing on scanned mesh

« on: April 07, 2025, 11:49:33 AM »

Hello Hans,

I see two possible fixes:

• is the Coordinate Reference System the same for the chunk and the mesh?
• Have you checked the "show Markers"-Button from the toolbar?

Hope that helps!

4

General / Re: Points in point cloud disappear when zooming in and out

« on: March 20, 2025, 10:41:34 AM »

Hi sbond,

it COULD be about the points situation in space. Every point has x,y,z-values for its position and when you alter the angle of your model, the point might not be visible from that perspective.

Have you already tried to edit those "noise points" in the Tie Points and build the Point Cloud with the clean data? For this step, i am having pretty good results with the "Gradual selection" Tool which becomes available from the Model Drop-down menu once you have the Tie Points active. Here you can select points by reprojection error and reconstruction uncertainty with the help of a slider.

Good luck!

5

General / Re: Segmentation

« on: March 20, 2025, 10:29:30 AM »

Yes, given a 3D model containing different buildings, I need some automated way to extract each building separately. Note that the buildings may overlap with each other, so they are mostly different by height, textures, etc.

I do not think this is possible as of now. The available solutions to your problem have been named already.

6

General / Re: Segmentation

« on: March 19, 2025, 04:12:35 PM »

Hi jrh87,

As far as i know, an auto-segmentation is not (yet) available.
One possible solution to your problem would be to generate your 3D-Model as you normally would and then set a boundary around the object you want your 3D-Model of.
In the export-dialog of the 3D-Model you can set the model to "clip to boundary shapes". That way you only export the wanted 3D-Model and nothing in the background.

A boundary can (to my knowledge) only be created on a DEM or Orthomosaic, so you would have to calculate those as well.

Set a boundary:
1) draw a polygon around the area you want to have a 3D-Model of in your DEM or Orthomosaic by using the polygon/polyline tool (image 1).
2) select navigation (the arrow-symbol in the toolbar) and select the just drawn polygon.
3) right click and "Set Boundary Type" --> "Outer Boundary", your Polygon should now turn into a hashed line (image 2).
4) right click on your 3D-Model and follow the export-dialogue. There you will have the opportunity to select "Clip to boundary shapes (image 3).

The exported 3D-Model will be clipped to your boundary and nothing outside said boundary will be visible in the final model.

Does this answer your question?
Good luck and all the best!

7

General / Re: DEM-Manipulation along waterbodies

« on: March 19, 2025, 01:47:46 PM »

Hi Alexey,

thank you very much for your reply - i am curious to try out said script once it is available! 

In the meantime, i tried Paulo's approach and got some interesting results.

From an existing Point Cloud, the workflow was like this:
1) Classify Ground Points via "Tools" --> "Point Cloud"
2) Classify Points via "Tools" --> "Point Cloud" (there does not seem to be an automatic function to classify points as water, so i did that manually with "Free-Form Selection" and "Assign class" in "Tools" --> "Point Cloud"
3) "Resize Region" to cover my sample
4) Build DEM from pointcloud with all points but water

The results are very promising and show a much smoother water surface, as the "Build DEM" command seems to interpolate all the missing parts on its own - no need to create a polygon which overlaps with the DEM on each side to get the heights.

The before image 1 (longitudinal) shows valleys and mountains on the water surface which differ up to 12 m, image 2 shows the lateral distribution of distortion. Interestingly, the overall water level in image 2 is pretty flat, even though it shows valleys and mountains. Image 3 shows the new water surface in longitudinal direction, image 4 the lateral water surface. In image 4, there seems to be quite an incline from the left bank to the right bank of about 0,5 m in water level, whereas the original (image 2) was kind of flat and more realistic when you ignore the distortion bumps.


So, to summarize my findings:

Generating a DEM from a classified Point Cloud without the water-class seems to be a feasible approach to my problem, even if it still requires to manually classify the waterbody.
Yet i am curious to see what Alexey and the Agisoft-Team come up with

Thank you all for your help!

8

General / Re: DEM-Manipulation along waterbodies

« on: March 18, 2025, 06:02:33 PM »

Hi! Now I get what you are telling me.
I know about the point classification and about creating a DEM from only ground points, but that would leave me with no elevation for the water. To get that elevation, I would need to create a polygon which slightly overlaps the river banks and then do "best fit plane" in the edit dem-menu... That's what I tried to express in my first answer when I was talking about the "empty river stretch" .

I will give that a try and report back as soon as I have some results.

9

General / Re: DEM-Manipulation along waterbodies

« on: March 18, 2025, 04:53:42 PM »

Or create a DTM from ground points only with interpolation...

Thank you again!
Could you point me in the right direction, as i am not entirely sure what you are talking about.

10

General / Re: DEM-Manipulation along waterbodies

« on: March 17, 2025, 10:14:42 PM »

Hi Paulo,

thank you for your insight!

Did I understand correctly?
I just create a polygon along the empty river stretch that overlaps slightly with the DTM to the left and right to get the somewhat correct height of the water level and fill it with best fit plane?
Or did you mean something else by saying " then use the DTM over river as its elevation..."?

I can see that working with a DTM, but for a DEM with Vegetation along the river banks this might not work...

11

General / DEM-Manipulation along waterbodies

« on: March 17, 2025, 01:14:22 PM »

Hello everyone! I am a long time lurker, first time poster on this forum and have a question regarding DEM alteration for waterbodies. My apologies in advance in case this has been asked before - the forum search did not come up with anything similar.

The company i work for is often tasked with the creation of Orthomosaics and DEMs along rivers (= inclined plane).
Orthomosaics turn out great everytime, DEMs in combination with GCPs (precision under 3 cm) are great for land but expectedly vary a lot for the water-parts.

I know that it is possible to manipulate the DEM in postprocessing by creating polygons and the "edit DEM"-Button on rightclick.

My current workflow for the river is: take water levels with GPS every 100 m or so in the field. In Metashape i draw a polygon for every water level marker i have in a way that the polygons slightly overlap each other. I then select one polygon after the other, right click --> edit DEM and set that polygons height to the measured height. That way i get a somewhat inclined plane as water level.

This works fine for short stretches of a couple hundred meters, but is unfeasible for stretches of a few kilometers.

Is there any way to recalculate the DEM as an inclined plane with, say, 2 given points? That way i could take one water level at the start and one water level at the end of the project and just interpolate between these two points.

The DEM within the river does not have to be 100% accurate, i just want to get rid of all the mountains and valleys and have it somewhat accurate - best fit plane often puts the water level a couple of meters higher than it actually is because of all the distortion.

Thank you for reading, i am looking for your input!