Vray for 3dsmax Matte Shadow option - Product rendering
So I was recently on a product rendering project where I needed to use Vray for 3DSMax, specifically looking at the Matte shadow option. The project involved the creation of 3d models, which would then be rendered photorealistically, for the purposes of an online shop. The client required all the renders on a white background, for uniformity. All in all, it was 11 product lines, with 3 to 5 variants in colours, and then 3 variants, in the component parts. So around 150+ products, and 7 renders were required for each one.
In order to completethings to a decent level of quality, and within the specified time frame, I decided to give VRay's Matte shadow feature a try. While it works great in theory, the results were different in practice.
See more details of the project and workflow here:
Vray Matte Shadow product render compared to the original
The issue was, that the value, and hue of the render from Vray matte shadow option did not match the product render: please see below:
As this did not produce consistent results, the solution was to use the existing backdrop renders, with some creative thinking.
Alternative Workflow for Product Renders on white background
As the client required all 150+ renders on the same white background, the solution, see video was to assign a material ID, to the backdrop, be sure to set the anti aliasing option in the render pass. I also added material IDs to parts that would need post processing, such as the metals plastics and glowing parts. Once the renders completed, I extracted the mattes for the backdrop using the material ID. For the contact shadows, I rendered out a Vray shadow pass, inverted the alphas, and that could have been used. But the clkient preferred no contact shadows. Another option might have been for the shadow:
Change the - Visible to camera option, in 3ds max's object proiperties. and render out just the contact shadow on the white backdrop. Depending on the shape and height of the models, this could be used on multiple renders.
The exiciting part of this job, is that there are no set workflows that work "everywhere", each project, to do it proper justice requires a unique workflow that works for "that" project.