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REAL Ambient Occlusion, Why we need it.


Roger_K
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0000492: REAL Ambient Occlusion

 

At the moment 3D Coat has a feature its calling Occlusion. Its Ok for a really basic lighting preview, if your willing to wait for it. There isnt really much point though because the render room will give you a far better lighting preview and it will do it much faster.

As a baked texture its very limited in its usage. In general you don't want any direct lighting information in your textures unless its a light map, In which case there are far better solutions that this. You want colour bounce for a start and correct area shadows. Direct light is going to be handled much better by the renderer.

AO in texturing and shading is generally used as what you might consider a Utility map, you dont used it directly, but more of a way of controlling certain effects.
for example:
 

  • Contact Shadowing
  • Dirt Distribution -With suitable settings you can create masks which are a great base for dirt maps
  • Cavity Mapping - These can be great for accentuation small details, wear maps for specular/reflection, dirt collection in tight crevices
  • Ambient Occlusion -Masking a environment probe to give the impression of Global Illumination
  • Bulge Maps - AO can be used as a displacement map to create surface indentations/ bulges around objects where they interface. great for mud

None of these things can be achieved easily with the current solution. To be able to achieve these effects you need the map to be a true occlusion map and you need to be able to control how it is created.

In a program like Mental Ray you have 3 main parameters that let you control the effects of the occlusion map.

Max Distance: How far a ray will probe for hits before its ignored.
001.jpg025.jpg
050.jpg100.jpg

Spread: how wide a cone of rays to shoot out from the point being sampled. in MR you get a 0-1 slider (the cosine of the cones spread angle)
01.jpg04.jpg
08.jpg12.jpg

falloff: the fallof value of the occlusion ray.
010-2.jpg050-1.jpg
10.jpg20.jpg

I really think this is an important feature to have in 3DC. especially for extracting detail from sculpts. To be honest I think 3DC could benefit from some additional baking feautres. In addition to AO, Curvature, and thickness maps (for faking translucency) would be great.
that said at this stage I'd be happy with AO

here is how Modo does it skip to 4:45 for the occlusion shading. (cheers Ben)

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thank you for bringing this back up , Roger! (and with such well prepared 'evidence') ;)

Maybe this isn't such a sexy feature request, but it sure is a hole in 3DC's armor, currently.

(hopefully Andrew can have a good look at this, as true AO has been on the request table for over

2 1/2 years) :)

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This is one of the few reasons I have to leave the app when creating content for games. As it is now my workflow is to dump all voxel layers out to objs and import them into modo, along with the retopo mesh (also from 3dc). I then do my normal and AO bake there since the results are so much better, and right now, worth the hassle of doing (sometimes massive) file transfers, especially with how many voxel objects I can end up with in a finished character sculpt.

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This is one of the few reasons I have to leave the app when creating content for games. As it is now my workflow is to dump all voxel layers out to objs and import them into modo, along with the retopo mesh (also from 3dc). I then do my normal and AO bake there since the results are so much better, and right now, worth the hassle of doing (sometimes massive) file transfers, especially with how many voxel objects I can end up with in a finished character sculpt.

totally agree, and find it very puzzling why this still goes unaddressed (after what I thought were pretty valid reasons 2+ years ago)

I guess it's a business choice to omit having a high-quality AO capacity in 3DC? <shrugs>

(I understand there are a ton of things on Andrew's plate, but this seems like one that wouldn't require revolutionary code <---coming

from a complete non-programmer, LOL) :pardon:

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:/ personally I'm close to giving up on 3DC and moving to a more polished/focused app like Zbrush or Mudbox.

It just doesn't seem to be going in the direction I thought it would when I bought it(not that I'm blaming anyone, its just not going my way). There are 3 ways to paint meshes none of which are up to date with the competition in terms of polish and speed. Don't get me wrong some of the features are fantastic, allot of them leave me ripping my hair out though.

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:/ personally I'm close to giving up on 3DC and moving to a more polished/focused app like Zbrush or Mudbox.

It just doesn't seem to be going in the direction I thought it would when I bought it(not that I'm blaming anyone, its just not going my way). There are 3 ways to paint meshes none of which are up to date with the competition in terms of polish and speed. Don't get me wrong some of the features are fantastic, allot of them leave me ripping my hair out though.

Which ones would those be? What I think may help here more than anything...in reference to this particular feature, is for everyone here who wants to see some movement on this...to e-mail Andrew (support@3d-coat.com) individually, and make the request. He not see the glaring need, and therefore has kept this request on the backburner.

I think the lengthy wait for filling a layer (with the FILL tool), is another sore spot.

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Which ones would those be? What I think may help here more than anything...in reference to this particular feature, is for everyone here who wants to see some movement on this...to e-mail Andrew (support@3d-coat.com) individually, and make the request. He not see the glaring need, and therefore has kept this request on the backburner.

I think the lengthy wait for filling a layer (with the FILL tool), is another sore spot.

there are many little things, next time I'm using 3DC ill write a list, stick it online here and see what are bugs and what im just doing wrong. Hopefully ill be doing some modelling soon. Im working on a new disney show at the moment and its primarily 2D.

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i use xnormal for baking ao maps, though i have to say that neither zbrush bakes true ao...

Lately i dont even use ao. I bake my normal maps and then i paint with cavity filters on and then blur it .Ao maps usually need tweaking anyway.

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Just checking... I honestly do not have a working understanding of what AO is used for though in this situation for 3D Coat.. if I'm baking the normals etc.. using the NM option from the Retopo menu.  What is a good distance setting for a Biped game character and is this now an improved setting in V4 as I note this discussion is a few years old yet seems to be a well targeted topic towards the questions I have.

 

Am just wanting to determine if 3D Coat is now a good option for this feature or if I need to still go outside of 3D Coat for this and also to determine if AO is needed for Game Characters.

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I have to create flatshaded 3d objects for integration into 2D animated shows. . .so I slap on the 3d-coat Ambient Occlusion layer to get general shading in the absence of lighting.  With the right amount of light and enough blurring I get good results and it saves me lot's of time from trying to paint in shadows.   Real AO calculations would be great . but I'm happy with the AO simulation we have now for my projects.

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