It could be a challenging task to reconstruct some types of thin objects, such as butterfly wings, sails, and so on. Starting from version Metashape 1.8 includes a special tweak that can improve the modeling results for thin objects.


Adding tweaks 

Before setting tweaks you need to perform photos alignment and build point cloud. Full information about general workflow in Metashape is available in our article -  3D model reconstruction.

1. Select Tools > Preferences... and open Advanced tab. Click Tweaks button on the Metashape Preferences dialog window.



2. We recommend using the following tweaks:

BuildModel/ooc_surface_blow_up = 0.95
BuildModel/ooc_surface_blow_off = 0.95


To add/create a tweak in the Tweaks dialog window use Add button. Double-click on the column Parameter to write a tweak and double-click on the Value column to add value for each tweak, as illustrated on the image below.  



Build Model

After settings tweak, you need to build a model of Ultra High quality. Select Workflow > Build Model and set parameters in the Build Model dialog window: 



   

After building the model use Tools > Model > Smooth Model... command. In the Smooth Model dialog window set the parameters as suggested on the screenshot below. Click OK button to apply smooth to your model.



Comparing results 

On the images below you may see the model created with tweaks implemented as described in the current article (on the left) and the model created via common workflow (on the right):



As you may see from the illustrations the suggested approach allows to improve the model significantly, however, there can still be some minor flaws listed below: 

  • there may be small holes in the object geometry.


  • some imperfections (see black shapes highlighted on the image below) may also be seen on the model in the Solid View mode. The problem is caused by the fact that the plane of one mesh triangle intersected with another mesh triangle plane.


To correct the described geometry issues (holes and black area) we suggest using Close Holes tool as described below:

 -  use Rectangle Selection tool from the Toolbar to select problematic area: 



 - delete the area using Delete Selection toll from the Toolbar: 



 - use Rectangle Selection tool again to select the area with hole, then run Close Holes command available from Tools > Model menu. Make sure to check the option Apply to selection in Close Holes dialog window:



Enable Apply to selection parameter to apply the tool only to the selected area.


  • if the object includes some areas that are thicker - the geometry may be roughened in such areas.


Before building using Metashape for a next project that includes an object of regular parameters (the geometry cannot be characterized as thin), please make sure that the tweaks have been disabled/removed. You may set the value for the tweaks as zero to disable them. If not disabled - the tweaks will be applied for the next projects run in Metashape.