Recently I stumbled across news of a standalone chassis under development for the SL40 Under Barrel Grenade Launcher. Consequently, I wanted to create a 3D version.
Developed by Lithgow Arms for the Australian Defence Force, the standalone chassis for the Steyr SL40 Grenade Launcher allows the launcher to be used independently, increasing options for use.
I used a Physically Based Rendering workflow as always, with a low and high poly model producing bakes and textures in Substance Painter and then exporting to both Marmoset Toolbag and Unreal Engine for renders.
17963 Tris Total
5109 Launcher (2K textures)
8140 Chassis (4K textures)
4714 Sight Assembly (2K textures)
Unreal Engine and Marmoset Toolbag both required different approaches to the optic.Because of this, I enjoyed finding ways to get the red dot reticle and iridescent glass working in real time. I used non lit geometry ahead of the glass to hide the reticle geometry and add the parallax effect to the sight for Toolbag, and BumpOffset to achieve a similar effect in Unreal Engine.
For the rainbow effect on the reflex sight, I used the Newton Rings secondary reflection in Marmoset Toolbag. While in Unreal Engine I combined a thin film effect iridescent shader on the colour channel with refractive glass to accomplish the result which is only visible from certain angles.