only to recall this challenge

Hi all G'MIC gurus!
Lyle told me he asked sometimes ago the same thing without success, but maybe now there is an open possibility
what about creating a G'MIC filter able to create from a given input image the corresponding 3d wireframe view?
something like this image found on Google

Trust me Diego; if it was simple, I'm sure David or someone else would have already done so. You can already create wireframes for 3D objects rendered in G'MIC, but you are asking to do the same for a bitmap. That's a pretty tough challenge I'm sure. Still, I would definitely like this if it can be done.

Lyle,
I'm convinced it's really difficult, but my implied question to G'MIC gurus is: is it IMPOSSIBLE?
(...hopefully not, given the power of G'mic))

It would require the retrieval of 3d information (at least 'depth') from a single 2d image, which is something almost impossible right now. It's not specific to G'MIC, that is *theoretically* impossible
There are few research work that tackled this problem (like "shape from shading"), but they work only with very specific images, as the pixel values of your images must be at least related to the 3d info you are trying to reconstruct.
For usual 2d color images, nothing can be done.

OK, thanks David, understood.

David,
what is your opinion if the goal is changed from 3d to 2d wireframe?
Lyle is experimenting a mix of G'mic filters to approach a wireframe output.
Maybe with a good combination of the capabilities of some of them something nice can come out.
For instance: Engrave is quite able to follow the main lines of the silhouette, if a net effect could be added (Delaunay style?) to simulate wireframe....

2d is another story. In this case, you can use the Artistic / Polygonize [delaunay] filter :

Yes, David, it's what Lyle (and myself) started from, but some improvement in the specific direction of wireframe (squares, for instance, instead of triangles) and more attention to the main relevant contours/significant lines (like Engrave does, for instance) could be interesting...

using Delaunay



using Engrave



"combining" the characteristics of the two (and changing triangles into squares for D.) could maybe provide a somehow wireframed output...

OK diego; this is the best I can do. Turns out elevation can do a pretty good job (either with straight image or convoluted image that I actually did).

OK lyle's various images convinced me to look at this wireframe thing
If anyone is feeling brave I've left an extremely hacky filter in testing -> garagecoder -> Wiremap

I'll clean it up at some point but the chances for now are things will break and people will scream, so be prepared!

note: hopefully be available for filter refresh within next 30 mins but the update schedule is a mystery to me...

Checked after refresh but do not see wiremap GC. Not sure if you decided to remove it or not.

I'm not sure how David's worked the update mechanism but it seems to have a mind of it's own!

I haven't removed it, chances are it will appear once I've given up waiting

I even updated to pre-release 1.6.9 but it's not showing for me yet either. The update is definitely there on github though

Edit: filter is there now, bear in mind it's incredibly rough and can of course be improved! Bed time for me now though.

Thanks for the update GC; I'll keep checking until the animation is no more. lol

Pretty cool GC. Much more friendlier than the way I'm doing them now. Has an issue with an object on a transparent background though (result is a transparent blank). Maybe future version can handle color too (do I asketh for too mucheth? lol).

excellent, GC!
I got a nice result

combined Engrave and the new GC Wiremap
forced one-thread on GC Wiremap to avoid artifacts

A quick note about "wiremap" - the alpha channel bug should be fixed with the next filter update (within 2 hours I hope). I notice multiply blend with colour layers can be interesting so I'll be having a look at that later, along with any other bugs/ideas. Got a busy day ahead though so it'll have to wait a bit!

waiting for the improvements to your excellent filter, GC...