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Author Topic: Lowpoly/Highpoly, looking for cage process  (Read 1450 times)

GGR

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Lowpoly/Highpoly, looking for cage process
« on: December 03, 2019, 04:59:37 PM »
Hello community,

Because everyone is not fitted as people dealing with hundreds of pictures, I'm trying to make my meshes lighter.

I noticed that it is possible to build virtuals cages around a lowpoly based on the normals of a highpoly so a high quality texture can fit on a lowpoly mesh.

I tryed with AM Pro 1.6.0 (build 9487) to generate normal maps from an highpoly and "bake" it on a lowpoly (decimated with the dedicated tool in AM Pro). It worked so I pushed on and imported the texture built on the highpoly but the result had been kind of an awefull patchwork. So basically I failed cause the normal map did not suit with the lowpoly mesh. I also tryed generate different normal maps with various mapping mode such as "keep uv" etc but without any kind of results.

I read that specifics paid softs can do so, but I'm wondering if anyone tryed and managed to do the same thing on AM.
If someone could share some of the processes that he use it would be most greatfull !

Alexey Pasumansky

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Re: Lowpoly/Highpoly, looking for cage process
« Reply #1 on: December 03, 2019, 08:50:28 PM »
Hello GGR,

Can you please specify your workflow? Also have you tried to use the High-poly model as a source for the texture generation of the Low-poly model?

I think that the "patchwork" issue related to the fact that the UV parameterization of the low-poly model (created during the Normal map generation) doesn't fit the external texture. So the external texture file (image) is applied using UV layout that doesn't fit that external texture.
Best regards,
Alexey Pasumansky,
AgiSoft LLC

GGR

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Re: Lowpoly/Highpoly, looking for cage process
« Reply #2 on: December 04, 2019, 04:59:05 PM »
Hey Alexey,

Basically, the workflow has been :

For the highpoly (HP)
- generating a HP mesh using depth map,
- working on topology via Instant Meshes,
- building a 10k diffuse map on this HP based on images with a generic mapping mode,
- building a 10k normal map based on the HP with keep UV as mapping mode,
- exporting this two maps based on the HP.

capture of the result 2019_12_04_diffuse_map_hp.PNG

For the lowpoly (LP)
- duplicating the HP then decimating it to get a 3k vertices LP
at this point, generated maps have vanished
- building a 10k normal map on this LP based on HP with a generic mapping mode,
- building a 10k diffuse map on this LP based on HP with a generic mapping mode.

capture of the result 2019_12_04_diffuse_map_lp_based_on_hp.PNG

To make sure their is a difference
- duplicating the 3k vertices LP
- building a 10k diffuse map on this LP based on images with a generic mapping mode.

capture of the result 2019_12_04_diffuse_map_lp.PNG

So I managed to build a diffuse map on a LP based on the normal map of a HP. Their is so far a little value in doing this when you compare 2019_12_04_diffuse_map_lp_based_on_hp.PNG & 2019_12_04_diffuse_map_lp.PNG, but the time spent using this workflow is too long for the result. But I'll try to look forward to improve it.

In the meen time, if you have suggestions...

Cheers
Gabriel

Mak11

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Re: Lowpoly/Highpoly, looking for cage process
« Reply #3 on: December 04, 2019, 05:36:00 PM »
The high poly mesh should only be used to bake normal/AO/etc on to the low poly mesh. Besides cleaning it there's no need to generate maps for it. All the work should be done on the low poly mesh (decimation, retopo, UV unwrap, baking etc).
Secondly this workflow only make sense if your diffuse is properly de-lit if the subject wasn't shot in proper lighting conditions.

Mak
« Last Edit: December 04, 2019, 05:39:44 PM by Mak11 »