1.7.4 Holes in mesh

[Eric Baird]

Using 1.74 (12950, 13028) with the highest quality settings, and highest quality alignment, I'm getting very wierd behaviour regarding holes.

Previously, where there were gaps in the data (such as a shiny featureless patch on an object, or the upper surface of a window-sill that was not directly visible from the ground), the software would either leave a gap in the surface, or patch over the gap by extrapolating from the surrounding surface. If it left a gap, then this could be simply fixed using Metashape's "fill holes" feature (or the equivalents on other software).

Now, the software interprets any gaps in the data as actual physical holes leading directly into the object, that it attempts to reproduce by creating curved-mouthed tunnels (one for each data-gap) that dive into the object's interior. When there are a number of these tunnels, the software then makes the inner mouths of these tunnels flare open again on the inside and link up to produce a new (invented!) interior surface, at a roughly constant depth from the outer surface.

I'm trying to model some solid stone statues standing on plinths, which have simple, singly-connected surfaces, and the models are turning into partially hollowed-out shells with lots of "wormholes" connecting the outer and inner sets of surfaces together. Lots of extravagant unwanted artificial interior structure that shouldn't be there, doesn't correspond to anything photographed, and which has to be carefully removed before the holes can be filled-in conventionally.

Is there any way to switch this new "clever" behaviour off, and revert to the older way of dealing with gaps?
 

[bgreenstone]

I had to revert back to 1.7.3 because 1.7.4 was generating very different geometry, and not for the better in my case.  My quick test of the 1.8 beta shows that whatever weirdness was happening in 1.7.4 seems to be fixed.

[Eric Baird]

Thanks, bgreenstone! I forgot that I'd updated the software at the same time that I changed my workflow. 

Reverting to version 1.6.6 (downloaded from the website) solved the problem.

I'm going to keep a copy of 1.7.4 on my harddrive for special cases where the "more aggressive" interpolation might be useful. ...
... I imagine that if one was modelling a set of ornamental cast iron gates, and only had photos taken from one side, the ability to aggressively treat all data-voids and ambiguous regions as actual  physical holes punched into the surface, and to have the remaining network of surfaces close up smoothly behind the actual photographed surface (to produce a second unphotographed but implied surface), could be a real time-saver. A kind of special dedicated "good for window frames, railings, and gates" mode.

But for everything else, I'll give 1.7.4 a miss.

Thanks for your help,
Eric 

[bgreenstone]

I may have been wrong about 1.8 beta fixing the mesh weirdness that got introduced in 1.7.4.  I've been running tests today and I'm having a chronic problem with it just like in 1.7.4.  Had to go back to 1.7.3 for now.

[Eric Baird]

Yep, I had the same behaviour on 1.8.x

I thought, as an experiment, I'd try it again on 1.7.4 with interpolation switched off altogether (and then use the automatic hole filling function afterwards) . And I still got the same "extrapolated" - style behaviour!   (double-skinned models, which aggressively attempt to close all holes by connecting them together, using a second surface behind the main surface).

The processing log dutifully showed interpolation as having being disabled when the mesh was processed, but it clearly wasn't.

So ... maybe ... there might be some sort of simple problem with the user interface (or how its flags are being interpreted), where the interpolation setting (disabled/enabled/extrapolated) is being ignored, and it's processing as "extrapolated" every time?

Dunno.   

[wojtek]

I may have been wrong about 1.8 beta fixing the mesh weirdness that got introduced in 1.7.4.  I've been running tests today and I'm having a chronic problem with it just like in 1.7.4.  Had to go back to 1.7.3 for now.

Yes, can confirm that 1.8.0 has the same issues found in 1.7.4 and 1.7.5

[Mak11]

IIRC this issue started back when the depth maps reconstruction workflow was introduced (in version 1.5) and seems to have been getting worse ever since unfortunately. I have already posted countless times about it on this board.

Mak

[Eric Baird]

Yes, can confirm that 1.8.0 has the same issues found in 1.7.4 and 1.7.5

Yep, agree, issue still present on 1.7.5 .

I'm finding that sometimes a model of a public statue on a plinth (which is not a closed surface) ends up with its interior riddled with "intestines" -- blobby interlinked networks of tunnels. And sometimes the interior ends up with a whole new hollowed-out interior surface. There must be some collision-avoidance or proximity-sensing code in action, because in the second case, the "new" interior surface seems to be a fixed distance below the real surface, and parallel to it.   

[lunar]

Hi
Same for me - 1.74 = 1.75 = 1.8
I requested a copy of 1.73

[CheeseAndJamSandwich]

Hi
Same for me - 1.74 = 1.75 = 1.8
I requested a copy of 1.73

https://s3-eu-west-1.amazonaws.com/download.agisoft.com/metashape-pro_1_7_3_x64.msi
https://s3-eu-west-1.amazonaws.com/download.agisoft.com/metashape_1_7_3_x64.msi

Just change the version number in the above url, and you can get any version that existed, i think.