Colour Chart / 3d Scan

[DanSHP]

Hello!

In order to push our visuals further, we are using 3d scans as much as possible, life is much easier this way. But some apprehension using colour charts.

So, it goes like this. We have a 3d scan from Textures.com. There is also a colour chart referenced with the material (below).

Now, if we want to match everything up correctly. What do we do next? I've searched the forum regarding this, but as usual it all just seems a bit jumbled up, with no succinct process.

But from what I've read, as far as I understand, we need to....

- Place a sphere in a max scene. Apply albedo texture to it.
- Place a 3d object representing the colour chart in a max scene. With correct RGB values for each colour.
- Then ensure the RGB values from the colour chart included with the scan, also match up with the RGB values on the model we've created.
- We need to match values for mid grey

...this is far as I get. Is this it?

As always, thanks for any help.

[DanSHP]

Also it would be best to do all of this this with a 1.0 dome light? Then switch to full HDRI and start adding spec, normal to fit etc?

[^Lele^]

The key part is the dome light with a white, 1.0f value, yes.
It will give you what's called GanzFeld Lighting, or Furnace lighting, which essentially multiplies the diffuse value by 1.0.
Alternatively, if the need is to just check colors, rather than shaders, you could also use the textures with a vrayLightMtl (@ 1.0 intensity, ofc), which would save you the hassle of a domelight.

[DanSHP]

The key part is the dome light with a white, 1.0f value, yes.
It will give you what's called GanzFeld Lighting, or Furnace lighting, which essentially multiplies the diffuse value by 1.0.
Alternatively, if the need is to just check colors, rather than shaders, you could also use the textures with a vrayLightMtl (@ 1.0 intensity, ofc), which would save you the hassle of a domelight.

Ok. Thanks, lele.

I have my sphere, and my domelight at 1.0. I have my texture applied to the sphere. I have a mid grey plane facing the camera at 90d next to the sphere. I'm in linear. What do I do from here? How do I cross reference the mid grey plane in my scene and the mid grey colour checker card provided?

My thoughts on this we are that using a colour checker, so that we can remove some doubt about the tonality of a material, not too light and not too dark etc. This harps me back to that substance validation thread I started, but I now have access to scans, I'm just perplexed on how to implement the colour checker cards that come with them. Do I even need to?

Also, looking into this further it would seem you need to have the camera settings used. They are not provided with the scans, therefore, what is point in supplying the colour checker?

[^Lele^]

Yeah, without the camera settings, there's not much point, as there isn't if you didn't get one Passport photographed in the same environment as the scan.
You could however start by assuming it's a "no exposure" render, and see if that takes you anywhere productive (so all you'd need in the scene is a 60% gray diffuse shader to check color values.).
You're right though, that without the exact shooting environment data, it could lead to a pointless excercise.