Banding When Making HDRIs Using Carrara Sky Presets

paul_a_schultz

I have been having reasonably useful success using the spherical camera in Carrara to create images that I import into Photoshop to create HDR images. Those are then useful in many graphic applications besides Carrara. Here's Big Bill in Blender with such an HDR sky: https://www.flickr.com/photos/pasfam/31394773565/in/album-72157677368113135/.

I have noticed that the gradient/fountain fills used for the zenith of the Carrara sky and realistic sky presets contains significant banding artifacts, which are more pronounced after the HDR processing. This makes them much less useful for many camera angles.

I can minimize the banding, I think, by using the sky editing features to add more detail up in the zenith area, so no big "flat" areas.

I can also add replicators and clouds, of course, and will do that next. But I like the quick results using the generated sky backgrounds.

Anyone else doing this? Any way to change any settings for the color blending in the basic (no clouds) fills for Carrara skys?

FifthElement

https://en.wikipedia.org/wiki/Dither

Carrara is rendering images in 8-bit color depth directly (256 shades of each color, red, blue and green) while many other renderers do this in 32-bit depth and then apply some form of dithering to a render. This form of artificial noise reduces/eliminates banding on subtle gradients, Bryce and Vue have this natively, reason why their skies render better and are more friendly to grading in Photoshop or Fusion.

Why would you make HDR's from Carrara's renders (?), Carrara's camera does not have any exposure adjusment  

cdordoni

I would suggest Luxus, or LuxusCore. Both are based on LuxRender and can export a 32-bit EXR which might help, although I have not used specifically for this issue. Luxus, a Carrara plugin sold by Daz, requires LuxRender to be installed. LuxCore is in beta now, you can get a beta copy from the LuxCore thread in the Carrara forum. It includes a version of LuxRender so there is no additional installation required.

cdordoni

BTW, LuxRender is free!

Dartanbeck

I was often curious if the Quality slider at the top of the Realistic Sky Editor would change this.

The zenith thing is just the spherical projection used to map the sphere, I think.

But the bands in the sky I think are often a result of the Aura effect settings for the sun and/or moon. So that's where I was wondering if the quality slider might diminish the obviousness of the transitions.

It looks like you're not using lens flares, which is good in my opinion.  think flares embedded into background maps is a mistake - though fairly common. Since flares are an artifact of lenses, our foreground elements cannot block them - but become obscured by them - hence it always being best to add those in the final stages.

Anyways... I have to say that I really like the result you're showing here! Blender Cycles engine? I have the Big Bill in my wish list. Very cool model! Nice job on the shaders and the creation of the HDR.

I did a little experimenting and really enjoyed it.

Here is my first attempt at a fully closed-in interior HDRI background sphere - no other lighting, no post work, rendered using Carrara's native render engine:

This one I made very much as you've detailed, adding many duplicates of the "City-Line Background" from mmoir's Carrara's BMF Landscape pack in the actual HDR exposure shots along with some volumetric clouds, and then used the same buildings and some more volumetric clouds in this render, which uses the HDR for lighting and background, though the light rays were added in post - again, rendered in Carrara

This is the same HDRI in DS (Iray) without any other lighting

This was one of my first HDRIs made in Carrara, brought into DS and used in the Iray dome with no other lighting

While this one I made just using a non-HDR spherical background rendered in Carrara, brought that into DS (Iray) and did add an extra light from behind - experimenting in Iray using HDR vs Spherical Background without being HDR

Dartanbeck

cdordoni said:

I would suggest Luxus, or LuxusCore. Both are based on LuxRender and can export a 32-bit EXR which might help, although I have not used specifically for this issue. Luxus, a Carrara plugin sold by Daz, requires LuxRender to be installed. LuxCore is in beta now, you can get a beta copy from the LuxCore thread in the Carrara forum. It includes a version of LuxRender so there is no additional installation required.

The next time I make an HDR I'll be trying Luxus for Carrara (Lexrender) as a 32-bit EXR to attempt a more true HDR output - looking into all of the settings to strive for something really cool. I don't think Carrara can use EXR directly, so I'll likely have to convert it - in which case I'll likely be trying Picturenaut for that.

paul_a_schultz

FifthElement said:

https://en.wikipedia.org/wiki/Dither

Carrara is rendering images in 8-bit color depth directly (256 shades of each color, red, blue and green) while many other renderers do this in 32-bit depth and then apply some form of dithering to a render. This form of artificial noise reduces/eliminates banding on subtle gradients, Bryce and Vue have this natively, reason why their skies render better and are more friendly to grading in Photoshop or Fusion.

Why would you make HDR's from Carrara's renders (?), Carrara's camera does not have any exposure adjusment  

Thanks for the information, I've dealt with 8-bit color before. I have a lot of WinFract fractals that are mostly useless these days because of it. I was testing the skys in Carrara because I saw some information about the spherical camera and how to set it up, and I wanted to test out the HDRI processing in Photoshop. Now I guess I have to get familiar with Bryce again. I like its skys better anyway. And, I have a Christmas budget for some commercial HDRI sets. Love the lighting in Blender, for example! Thanks again.

paul_a_schultz

Dartanbeck said:

I was often curious if the Quality slider at the top of the Realistic Sky Editor would change this.

The zenith thing is just the spherical projection used to map the sphere, I think.

But the bands in the sky I think are often a result of the Aura effect settings for the sun and/or moon. So that's where I was wondering if the quality slider might diminish the obviousness of the transitions.

It looks like you're not using lens flares, which is good in my opinion.  think flares embedded into background maps is a mistake - though fairly common. Since flares are an artifact of lenses, our foreground elements cannot block them - but become obscured by them - hence it always being best to add those in the final stages.

Anyways... I have to say that I really like the result you're showing here! Blender Cycles engine? I have the Big Bill in my wish list. Very cool model! Nice job on the shaders and the creation of the HDR.

I did a little experimenting and really enjoyed it.

Glad you like the rendering, I have been working with Blender seriously for a year or so, and like it because there is a local user group and lots of other support.

I have a pretty good pipeline for exporting Carrara models to Blender now. The Utah Raptor in this one was my first attempt at transfering a posed model. Very encouraging!

This is the best I could do 5 or 6 years ago, using Carrara:

This is a nearly complete version done in Blender, with a commercial HDR background:

 

 

paul_a_schultz

paul_a_schultz said:

This is the best I could do 5 or 6 years ago, using Carrara:

This is a nearly complete version done in Blender, with a commercial HDR background:

Oops, bad links. Try these:

paul_a_schultz

paul_a_schultz said:

paul_a_schultz said:

This is the best I could do 5 or 6 years ago, using Carrara:

This is a nearly complete version done in Blender, with a commercial HDR background:

Oops, bad links. Try these:

Can't get them to work, so here they are as plain text:

https://www.flickr.com/photos/pasfam/5845427891/in/album-72157624417109574/

https://www.flickr.com/photos/pasfam/31384342781/in/album-72157677368113135/

Sorry about that.

paul_a_schultz

FifthElement said:

https://en.wikipedia.org/wiki/Dither

Carrara is rendering images in 8-bit color depth directly (256 shades of each color, red, blue and green) while many other renderers do this in 32-bit depth and then apply some form of dithering to a render. This form of artificial noise reduces/eliminates banding on subtle gradients, Bryce and Vue have this natively, reason why their skies render better and are more friendly to grading in Photoshop or Fusion.

Why would you make HDR's from Carrara's renders (?), Carrara's camera does not have any exposure adjusment  

Wow! Really good results rendering and exporting spherical HDRs from the Bryce 7 Sky Lab. Well worth the effort re-learning the Bryce interface. And don't need Photoshop at all this way. Thanks!

FifthElement

Yep, Bryce is like a Beatles song, old but still relevant 

Chohole

FifthElement said:

Yep, Bryce is like a Beatles song, old but still relevant 

I resemble that remark     

Dartanbeck

Chohole said:

FifthElement said:

Yep, Bryce is like a Beatles song, old but still relevant 

I resemble that remark     

LOL

 

paul_a_schultz said:

paul_a_schultz said:

This is the best I could do 5 or 6 years ago, using Carrara:

This is a nearly complete version done in Blender, with a commercial HDR background:

Oops, bad links. Try these:

If you still have the Carrara scene saved, try it again - this time, in the render room, set Gamma Correction = 2.2