Cross section for multiple slices

[EnchantedCJ]

Dear guys,

I'm new to the cross section tool, so I try to follow the tutorial in https://www.cloudcompare.org/doc/wiki/i ... ngle_slice

What I try to produce is several envelope polylines in each slice, but I always get envelops that are connected to each other, which I show in the attachment. However, in the very last picuture in the tutorial (down below the page in the above link), the envelope of the monster's legs seams to be separated. I wonder how to achieve that. Thanks!

Best,

Sun

[daniel]

Have you tried the new 'extract contour' tool in the 2.12 version? It's the way to go if you want multiple contours (for each 'island').

Otherwise, the envelope is always unique inside a slice.

[EnchantedCJ]

Have you tried the new 'extract contour' tool in the 2.12 version? It's the way to go if you want multiple contours (for each 'island').

Otherwise, the envelope is always unique inside a slice.

Thank you, Daniel. I've tried "extract contour" and that works fine. BTW, I found that the generated contours are zig-zag in a few discrete directions (0,45,90...degree), is this a feature of the tool and cannot generate boundaries with arbitrary directions like the "envelope"?

[daniel]

I guess it depends on the grid step? (but I may misunderstand what happens ;)

[EnchantedCJ]

I guess it depends on the grid step? (but I may misunderstand what happens ;)

Sorry, I haven't made my problem clear. I upload the result in the attachment. The envelop (green line) is extending into arbitrary directions, while the contour (white line) goes in several regular directions. I think you mean this is caused by the gridding calculation of the contour, is that true? Thanks.

[daniel]

Yes, the 2 methods have very different ways of working. One projects the points inside a plane and use an expansive algorithm to try to determine the concave hull, and the other simply relies on a regular grid (just as the 'Rasterize' tool).

[EnchantedCJ]

Yes, the 2 methods have very different ways of working. One projects the points inside a plane and use an expansive algorithm to try to determine the concave hull, and the other simply relies on a regular grid (just as the 'Rasterize' tool).

Thank you for your reply! Now I understand how it works.