Help: Filling mesh holes, second colour

Greetings

I’m new to blender, but need to edit 3D model for my thesis project.
I am scanning objects using a laser scanner, these mesh’s have gaps or holes sections were the scanner didn’t capture sections of the model, i want to be able to fill these holes with a second colour so the areas the scanner has capture and the areas filled by the computer can be seen easily

Any help the community could be proving will be most welcome

Well, if you go into Edit Mode and hit Ctrl+Alt+Shift+m while in Vertex Select or Edge Select Modes, it will select all nonmanifold elements.

That will show you the holes, but if you want something more permanent this is where my solutions take a turn for the weird.

You could hold Ctrl and hit Numpad “+” to grow the selection, then click Assign for your brighter material slot.

You could also hit e to extrude those pieces out a bit and then Assign the bright material to the pieces.

If neither of these works for you let us know and we can come up with something else. For example, with some scripting you could iterate over all the loops that border a hole, extrude them, then do the equivalent of Alt+m > At Center to cap them out with triangle fills.

-rking

As I assume your final intention is not to render the image as such but to use the model itself. My method would use scripting and BMesh (will require a nightly build).
Iterating through all the gaps in your mesh you can fill them with an n-gon and then separate it from the original mesh. When all holes are close you can join all your separated objects together. This results in two meshes, your original and a mesh representing all the holes.