Gain Issue

Announcements, requests and support regarding the 3DS MAX exporter
Post Reply
6 posts • Page 1 of 1
ArielLyn43
Posts: 11
Joined: Fri Aug 26, 2016 1:43 pm

Gain Issue

Post by ArielLyn43 » Sun Feb 19, 2017 6:18 am

Indigo 3.8.31
3D Max

Hi Everyone,

I have been trying to figure out why I have been getting material colors that are too light in Indigo and may have found a gain issue / conflict. I'm hoping its just a setting issue you can help me solve.

I was running a test when I found the problem: I created 4 ball models and a mid grey background plane. The balls were assign colors derived from spectral data I collected. Ball 1 used the spectral data directly entered into its igm file. Balls 2-4 used linear adobe rgb values derive from Bruce Lindbloom's spectral converter. Balls 2-4 varied only by their designated CIE standard illuminate.

The color sampled was a dark chocolate brown. In Max's environment preview window the colors appear a dark brown when the auto 2.2 gamma correction is off. When exported to Indigo they appear dark brown in the environment preview and the color samples in the material editor, but appear cinnamon color in the render window and saved images.

Now here's were it gets more interesting: When I change the color gain of a ball in indigo, specifically lowering it and raising it back to 1, the color of balls 2-4 change to and render the expected dark chocolate color. There is no gain control in materials for the tab data of ball 1 so I can't tweak it and it remains a cinnamon brown.

Any ideas what might be causing the colors to be too light until the gain is wiggled?

Thanks

ArielLyn43
Posts: 11
Joined: Fri Aug 26, 2016 1:43 pm

Re: Gain Issue

Post by ArielLyn43 » Sun Feb 19, 2017 10:40 am

So the plot thickens: I found in the scene file that when I wiggled the gain control in Indigo it changes the Max 1.0 gamma settings to 2.2 gamma. My RGB color values are all linear 1.0, Max outputs them as 1.0 to the scene file; why would Indigo change the gamma to 2.2? The color looks right at 2.2 gamma, but it just doesn't seem to make since in a linear workflow.

ArielLyn43
Posts: 11
Joined: Fri Aug 26, 2016 1:43 pm

Re: Gain Issue

Post by ArielLyn43 » Wed Feb 22, 2017 2:05 pm

So I think I have a handle on what is happening.

1) My color data was flawed do to testing error, so Indigo was rendering the correct color based on the spectral / RGB data exported from max.

But,

2) When I wiggle a color's gain control in Indigo, the program is changing the material albedo from 1.0 to 2.2 gamma darkening the colors rendered.

3) Most likely the Indigo sample colors and the colors in the material editing window are being treated as 2.2 gamma making them appear darker.

To the best of my knowledge, Indigo is rendering the colors correctly when working with Max's 2015 default linear space; so long as you do not attempt to adjust the gain in Indigo. I'm going to need to adjust my light intensity in Indigo and will be keeping a close eye on the scene file to see if doing so will have an effect on the gamma settings.

User avatar
Jay-ko
Posts: 137
Joined: Mon Nov 12, 2012 7:28 pm
Location: Paris

Re: Gain Issue

Post by Jay-ko » Thu Feb 23, 2017 4:48 am

You mean, into "Indigo renderer" ? That affect the futur recorded igs file?
errare humanum est

ArielLyn43
Posts: 11
Joined: Fri Aug 26, 2016 1:43 pm

Re: Gain Issue

Post by ArielLyn43 » Sun Feb 26, 2017 10:59 am

Hi Jay-ko,

When using the Indigo plugin for 3D Max 2015:

The Indigo scene file created maintains the linear gamma 1.0 settings for albedo. If a gain adjustment to albedo is made in Indigo's user interface, prior to selecting render in Indigo, the 1.0 gamma settings of the selected colors are changed to 2.2 gamma.

The altered gamma settings do not effect 3D Max's files and exporting the scene again generates a new scene with the correct gamma settings. But, if the user is unaware of the changes to gamma, the effected colors will render to dark and the scene may be saved effecting future renders of that scene.

tar_gniK
Posts: 152
Joined: Wed Apr 13, 2011 7:36 pm
Location: London, UK
3D Software: 3ds Max
Contact:

Re: Gain Issue

Post by tar_gniK » Mon Feb 27, 2017 11:03 pm

Finally!! I thought it was just me, and I have actually mentioned this before here.

The exporter has gamma on or something. If I make a material in 3dsMax, the colour in the renderer is completely off. It is imperative for the work I do that the colours are 100% to the client's specification.

There needs to be an option to turn off the gamma in IndigoMax. Even if I have gamma off in Max itself, the exporter sends to Indigo colours that are completely wrong. To this very day, I cannot touch IndigoMax with a bargepole unless this problem is fixed.

Meanwhile, I am still (3-4 years later and to my cost because I have use an older version of Indigo) using Maxigo.

Post Reply
6 posts • Page 1 of 1

Who is online

Users browsing this forum: Semrush [Bot] and 1 guest