Tag Archives: wedge study

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.