Tag Archives: render

Wedge Study 3 – Headlight colour temperature

Headlight Colour

At some point in my car project, I am going to want to ‘turn on’ the headlights and create a volumetric look as though there are particles in the environment. So as I searched for a third attribute to test, I figured I would test subtle variances in the colour temperature of the light.

I checked ‘use color temperature’ in the Arnold settings for the spotlight and iterated up in increments of 100 degrees kelvin

5000 degrees Kelvin

5000 degrees Kelvin

5100 degrees Kelvin

5100 degrees Kelvin

5200 degrees Kelvin

5200 degrees Kelvin

5300 degrees Kelvin

5300 degrees Kelvin

5400 degrees Kelvin

5400 degrees Kelvin

5500 degrees Kelvin

5500 degrees Kelvin

5600 degrees Kelvin

5600 degrees Kelvin

5700 degrees Kelvin

5700 degrees Kelvin

5800 degrees Kelvin

5800 degrees Kelvin

5900 degrees Kelvin

5900 degrees Kelvin

 

What I have learned –

I tested the colour spectrum between slightly yellow light at 5000 through netral ‘daylight’ at 5500 and then through to a bluer light at 5900. I would depend on the manufacturer but I think I will just do what feels right for the scene. Now I have a great look up chart.

 

 

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Wedge Study 2 – Car wheel rims

How ‘shiny’ do I want the wheel chrome to be? In my test render at maximum shininess, they seemed to be a distraction and drew too much attention to the eye.

I am not working for a car company and matching an established look, rather I am creating something that looks pleasing so its up to me to find the balance. I am testing the ‘roughness’ value on the specular properties starting at zero for maximum shine and going up in increments of .05 –

Specular roughness at 0

Specular roughness at 0

Specular roughness at 0.05

Specular roughness at 0.05

Specular roughness at 0.1

Specular roughness at 0.1

Specular roughness at 0.15

Specular roughness at 0.15

Specular roughness at 0.2

Specular roughness at 0.2

Specular roughness at 0.25

Specular roughness at 0.25

Specular roughness at 0.3

Specular roughness at 0.3

Specular roughness at 0.35

Specular roughness at 0.35

Specular roughness at 0.4

Specular roughness at 0.4

Specular roughness at 0.45

Specular roughness at 0.45

 

What I have learned – 
As the roughness value goes up, the wheels start to move into a flatter, more diffused plastic kind of look. The renderer mimics a surface the has some granular texture which diffuses the light rays and bounces them out at angles. I prefer the lower values and the more chrome like look but for my taste .15 is just enough to break up the harshness and aliased feel you get at 0.

 

Wedge Study 1 – Car windscreen

Below is wedge study for render attributes using the Arnold renderer – I decided to focus on car materials as this will help in look development for a car project I am doing. The car project will be rendered in a HDRI environment for integration with a live action plate but to make it easy to assess the shaders on their own merit, I have simulated studio lighting conditions –

Wedge study 1 – Windscreen glass
One of the materials that was challenging me a bit was the windscreen glass. To simulate different reflection and refraction properties at different grazing angles. Of particular importance is the ‘reflectance at normal’ value in the specular properties so I began changing the values by increments of 0.3 and saving swatches –

reflectance at normal set to 0

reflectance at normal set to 0

reflectance at normal set to 0.03

reflectance at normal set to 0.03

reflectance at normal set to 0.06

reflectance at normal set to 0.06

reflectance at normal set to 0.09

reflectance at normal set to 0.09

This one above is the one that feels about right to me.

reflectance at normal set to 0.12

reflectance at normal set to 0.12

reflectance at normal set to 0.15

reflectance at normal set to 0.15

reflectance at normal set to 0.18

reflectance at normal set to 0.18

reflectance at normal set to 0.21

reflectance at normal set to 0.21

reflectance at normal set to 0.24

reflectance at normal set to 0.24

reflectance at normal set to 0.27

reflectance at normal set to 0.27

What I have learned –
Given that there is a large overhead softbox light, the higher values look really burned out. However, if the value is too low, the glass is too transparent and looks fake.
A value of about .09 seems to look about right for my tastes. This may need to be reduced in a HDR environment where there are sharper things like tree branches reflecting but for now I will call that good.