Car Set-up & Rendering Tutorial
I have covered topics of modelling wheels and tyres for cars, as well as grading renders. it seemed fitting therefore to also cover a quick mini-tutorial for setting up rendering of cars. The setting for car renders is highly subjective, and many people favour outdoor locations using HDRI maps for the lighting and environment. They certainly have their place, there is no denying, however I find the simplicity of a completely neutral environment hard to beat. It offers no distraction from the main subject, and shows the lines and beauty of the car like few other environments can.
So this then is how I do mine, producing clean renders in colour neutral settings. Of course the effective environment colour is yours to choose, white is just my preference.
Some Super Simple Modelling
First things first is the unseen environment. In modelling terms, it doesn’t get much simpler. I made a large box structure, which truth be told needn’t be more than an actual box. I modelled mine curved, but for this rendering set-up, it actually doesn’t need to be. This initial outer box is the black void seen in reflections, and as such it’s surface attributes should be set as R:0 G:0 B:0 for colour and 0% for diffuse. Within this outer black box, I have added three rectangular panels, all the same lengths, but slightly varied widths. Their normals are pointing toward the 0,0,0 world centre. These panels will provide the white areas for reflections in the paint and on glass, but will also provide light. Surface attributes as a good starting point are colour R:255 G:255 G:255, diffuse 0%, and luminosity of 275%.
The last modelling task is the ground. For this I create a plane which gently curves up in the background. This is a good generic ground that can be used outside of this type of scene set-up, as the ground also provides a backdrop. For this render the ground has colour set to R:140 G:140 B:140, diffuse of 100% and no specular or reflections.
In order to give a little flexibility for tweaking post render, set the light panels and ground objects to be excluded from the alpha channel. Under object properties, make sure it says that the alpha channel in Unaffected by Object. This will ensure the alpha channel will only have the car in it. The other options can all remain as default.
For the outer black box, untick the Cast Shadow, Self Shadow, and Receive Shadow. Make sure you tick Unseen by Camera and Unaffected by Fog. This means that the black box never directly shows up in view of the camera, and unaffected by fog means it will always be fully visible to reflections (otherwise all reflections would be white).
With your car loaded in, we need to set fog as enabled. I always use the realistic mode, but for this purpose it really doesn’t make a vast difference. The fog is simply serving the purpose of blending the background and ground in to a unified background. To this end, ensure you have Use Background Colour ticked, and set the background colour in the scene to R:239 G:239 B:239.
So what we now need to do is get or fog set right. You need to adjust the fog to kick in just beyond the boundary of the farthest most visible scene element. If you have the OpenGL set to show fog, you can see the fog clipping the car in the viewport. F-Prime or VPR will of course show the same thing rendered.
Here the fog is now just beyond the far corner of the car. With the minimum and maximum distances almost the same, the fog creates a very distinct curtain, but you can expand the gap between them to create a more gradual blend should you wish some visible ground evidence behind the car.
The Finished Render
The finished render which has also been graded. Read HERE to find out how.