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Converting transition colors to solid color

Posted: Sat Mar 03, 2018 12:21 pm
by NaikJoy
How could I convert the color from the roof top and the wall to a blue color in this example?
So I could extract the whole buildings..not just rooftops. :)

Image

Re: Converting transition colors to solid color

Posted: Sat Mar 03, 2018 12:27 pm
by daniel
Wow... is the color coming from a scalar field or is it per-vertex RGB info?

Re: Converting transition colors to solid color

Posted: Sat Mar 03, 2018 12:43 pm
by NaikJoy
Oh you replied already :O that was super fast. Its coming from the scalar field. I read around the forum a few things so I know that I can adjust the slider and extract from the slider. So I extracted the rooftops and then I extracted the ground and merged them. I wanted to triangulate the buildings and be able to extract just them without the ground. So I won't need to delete it manually later.

I really wanna know how to do this.. it would help me a ton
Otherwise I'm trying real hard to make a racing game.
If I can do 1 square KM look like a racing game from 1998 I can then make 220 km to look like that
Image

Re: Converting transition colors to solid color

Posted: Sat Mar 03, 2018 1:37 pm
by daniel
Well, if you have a scalar field (and in fact if you have already extracted the point corresponding to the roof tops), then you can compute the distance between the points on the roofs and the other points (the ones on the ground) with the 'Tools > Distances > Closest Point Set' tool (use the ground points as the 'compared' cloud, and the roof tops as the 'reference' cloud). This way, you will get the points of the ground that are the closest to the roofs, and hopefully it will be the base of the walls?

It's just a random guess. CloudCompare is not really meant to work with meshes ;)

Re: Converting transition colors to solid color

Posted: Sat Mar 03, 2018 1:48 pm
by NaikJoy
Oh thank you so much for the reply. I will do as instructed here. Gonna go try this out now.
I'll be back if I get stuck somewhere along the way.

Re: Converting transition colors to solid color

Posted: Sat Mar 03, 2018 2:49 pm
by NaikJoy
It doesn't create enough points to make good walls. I tried a few combinations but its no good.
Is there any other way?
Would it help if I gave you the file?
https://ufile.io/3zl1x

EDIT:
I think an option should be created that could turn that blue-gray transition into a solid blue.
I would really come in handy to me now now to extract just buildings.

Re: Converting transition colors to solid color

Posted: Sat Mar 03, 2018 3:15 pm
by daniel
Well that's not that simple (the color is automatically interpolated by OpenGL here, it's purely visual).

You could also try to play with the scalar field that gives you the 'blue' color (is this the classification) by spatially enlarging it (for instance with Edit > Scalar fields > Smooth) for instance.

I'll try with your file if I find the time.

Re: Converting transition colors to solid color

Posted: Sat Mar 03, 2018 3:24 pm
by NaikJoy
Thanks again :)
You give me hope.

I'll follow your suggestions.
I'm a noob. I'll come back if something goes wrong.

Re: Converting transition colors to solid color

Posted: Sat Mar 03, 2018 3:31 pm
by daniel
Okay I extracted the class 6 from the LAS cloud (for the roofs) and the class 2 (for the ground).

Then I used the 'Closest Point Set' tool with the ground (class 2) as reference and roofs (class 6) as compared (the opposite of what I told you I believe ;).

And then I get a not that bad result:
cc_buildings.JPG
cc_buildings.JPG (71.74 KiB) Viewed 1769 times
I mean it would be hard to get a much better one. Apart maybe by playing with the scalar field beforehand (but I won't have to try).

Re: Converting transition colors to solid color

Posted: Sat Mar 03, 2018 3:36 pm
by NaikJoy
Hmm.. I'm sceptically worried this might not be enough for a good result in 3D and ripping.
But I will do this. I'll play around with it and hopefully get results.

Thanks again Daniel!
Cheers!
https://www.youtube.com/watch?v=BQIt6m6pbJU