what i usually like to do is to save as a project at a different location (which creates a new tex folder with all textures) and then save multiple files with different render/save settings and cameras while keeping the master file. This way i have every file for every render i made if the client wishes to return to a previous version.
If there are lots of expected changes during the creation process i make a simple xpresso setup to turn things on/off, change hypernurbs settings, etc with one click making the file saving process at least a bit more comfortable.
One disatvantage of different render settings is that you still have to rename the file output paths every time if you dont wish to overwrite.
Maybe there are some plugins out there helping to make life easier.
This has just been posted over at GSG:
The plugin is not yet finished but it could be interesting for your project.
i think UV Mapping & Photoshop will be one way to go. From your photoshop file you can create alpha masks for the spectular channel - dust is non reflective and dull.
To create realistic (believable) dust on a material you need to understand the "physics" of dust. The dust layer is thicker on the top side and almost none on the bottom side of things because of the way dust covers the objects. Dust can easily be wiped off so you will more likely see spots where the object came in contact with other objects creating scar like marks or fingerprints on the places where you would touch the object. For example a dusty car but still in use would show less dust on the car door handle area.
The second thing would be the environment. Usually dust as a warm grey color, but depending on the environment its color can differ. For example the house dust has a different color and different shape created by the indoor fabric materials.
You can also try out procedural Materials to achieve this effect but it is a "science of its own" to get the hang of it.
In this topic you can find a discussion about procedurals:
The first link to Carles Piles' site seems to be offline, but you can use google's cache to see the tutorial and download the scene file to learn about how they work:
By the way this is the most impressive procedural material i've come across just by looking at the sheer uncountable amount of different layers and techniques used.
It is always better to create individual objects for the individual parts because they are easier to manage later.
For the lights i would create an indentation inside the mesh and put the light mesh in there - so that they are "enclosed". This way if you later decide to "turn the lights on", they won't shine inside the car's interior ;)
Take a look at these nice Audi C4D project files (also the S5) made by Tom3D:
When you saved 'B', 'A' has been overwritten - so there isnt any 'A' anymore ;)
You need to have one file per render queue with its own render settings and file-save paths. Just save multiple c4d files.
(i like to call the files something like Filename_Camera1_25FPS_F0-F50.c4d)
it's hard to blur something that is in the foreground using standard blur because technically the object in the foreground covers what is behind it which will give you the sharp edge. So in some way the software needs to recreate what is behind the object and then put the blurred object over it again.
First group your back wheels so that the parent null's z axis is pointing in the direction of the front wheel - this will be important later. I will call this null "rear axle".
Create a constraint tag on the rear axle with clamp selected. Add your front wheel as target with align: Z+ and distance: (the actual distance you have between the front & back axle)
On the same constraint tag on the rear axle also select PSR. In the PSR tab "constraint" deselect everything except Y. In "target" click on "add", drop your front wheel in there and check P only. (this will make the rear axle stay on the same Y position as the front wheel)
Then add a target tag to your rear axle with your front wheel as target.
Finaly draw your spline and fit your front wheel with an align to spline tag.
i guess by "sub frame motion blur" you mean "scene motion blur" - just to make sure we're talking about the same thing ;)
To decrease rendertime you could try to lower the samples of the shadows, GI, etc. since the scene motion blur will merge the "sub frames" together and make it smooth again - maybe this can speed it up while maintaining the quality.