Holes in mesh: is there a way to solve the problem?

[Denis]

Dear all,

I'm quite new to Meshroom.

I have some strange problems with mesh: often, the point cloud from the SfM looks really good, but sometimes the Mesh have strange jagged holes. See the two sets of examples bellow.

Somehow, adding photos to cover the affected areas did little to solve the issue.

Could you point me to a tutorial, or suggest parameters I could fiddle with to obtain a better mesh?

Maybe the problem is with the dataset: the statues are outside, so obviously the light changed a bit while I was doing all the photos. Yet, it would be great if I could salvage the situation.

For info: these are large datasets, so they take several hours to compute completely. So if you have a good tip, it will take me time to check the results.

See the difference in the neck and head of the horse and the helmet of the horseman:

Another dataset, see the complicated holes in the helmet.

Another more minor issues is that the textured meshes always look dark compared to

Other than that, I'm really amazed at the results. For large mate objects such as statues, the results are beyond my expectations!

Best wishes,

Denis

[Fabien Castan]

Hi Denis,

You could try to change some advanced parameters on the Meshing node, to analyze where the problem comes from:

invertTetrahedronBasedOnNeighborsNbIterations=0

nbSolidAngleFilteringIterations=0

maxNbConnectedHelperPoints=-1

You need to enable the advanced parameters in the Parameter Editor widget ("..." on top right of the param editor).

Best,

---

De : alice...@googlegroups.com <alice...@googlegroups.com> de la part de Denis <mimet...@gmail.com>
Envoyé : lundi 30 août 2021 16:44
À : AliceVision <alice...@googlegroups.com>
Objet : Holes in mesh: is there a way to solve the problem?

 

⚠️ Do not click or open unknown attachments ⚠️ **

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[Denis]

Hi Fabian,

I'm on Meshroom 2021.1.0 on Windows, and if I am not mistaken, some of these parameters (called attributes  in this version) have slightly different names.

I changed

Tretrahedron Neighbors Coherency Nb Iteration : from 10 to 0

and

Nb Solid Angle Filtering Iterations : from 2 to 0

For the last one about helper points, I'm not sure which one it is. Is it "Helper Points: Max Segment Size"?

Here's what I have with advanced ticked (default parameters, before I changed the values as suggested):

Best wishes,

[Denis]

About the holes I observed, using the parameters suggested (see below) did reduce the size of the holes a little, but did not eliminate them. I since add the same problem on other dataset.

Also, I checked: on these datasets, I have multiple camera angles pointing in the right direction, and the photos were aligned correctly.

I wonder if the trouble could be with depthmaps maybe?

Parameters

Tretrahedron Neighbors Coherency Nb Iteration :  0

Nb Solid Angle Filtering Iterations :  0

Helper Points: Max Segment Size : -1

Maybe I'll try to do a new set of photos for these statues, see if if changes something.

The other option is too learn how to close these holes with Blender, that will take time though, I'm not used to Blender yet.

Denis

On 31/08/2021 00:00, Denis wrote:

Hi Fabian,

I'm on Meshroom 2021.1.0 on Windows, and if I am not mistaken, some of these parameters (called attributes  in this version) have slightly different names.

I changed

Tretrahedron Neighbors Coherency Nb Iteration : from 10 to 0

and

Nb Solid Angle Filtering Iterations : from 2 to 0

For the last one about helper points, I'm not sure which one it is. Is it "Helper Points: Max Segment Size"?

Here's what I have with advanced ticked (default parameters, before I changed the values as suggested):

Best wishes,

On 30/08/2021 22:57, Fabien Castan wrote:

Hi Denis,

You could try to change some advanced parameters on the Meshing node, to analyze where the problem comes from:

invertTetrahedronBasedOnNeighborsNbIterations=0

nbSolidAngleFilteringIterations=0

maxNbConnectedHelperPoints=-1

You need to enable the advanced parameters in the Parameter Editor widget ("..." on top right of the param editor).

Best,

---

De : alice...@googlegroups.com <alice...@googlegroups.com> de la part de Denis <mimet...@gmail.com>
Envoyé : lundi 30 août 2021 16:44
À : AliceVision <alice...@googlegroups.com>
Objet : Holes in mesh: is there a way to solve the problem?

 

⚠️ Do not click or open unknown attachments ⚠️ **

Dear all,

I'm quite new to Meshroom.

I have some strange problems with mesh: often, the point cloud from the SfM looks really good, but sometimes the Mesh have strange jagged holes. See the two sets of examples bellow.

Somehow, adding photos to cover the affected areas did little to solve the issue.

Could you point me to a tutorial, or suggest parameters I could fiddle with to obtain a better mesh?

Maybe the problem is with the dataset: the statues are outside, so obviously the light changed a bit while I was doing all the photos. Yet, it would be great if I could salvage the situation.

For info: these are large datasets, so they take several hours to compute completely. So if you have a good tip, it will take me time to check the results.

See the difference in the neck and head of the horse and the helmet of the horseman:

Another dataset, see the complicated holes in the helmet.

[Jim George]

I tried something after finding that everytime I ran a set of images I was getting worse results that before. I shut my computer off and restarted it (I even unplugged it) The next time I ran the images I got perfect results.

To view this discussion on the web visit https://groups.google.com/d/msgid/alicevision/aac6657f-7b58-0189-5688-fd0084b56845%40gmail.com.