Motion Blur in Mental Ray

[Pyro777]

Hello everyone,

I'm trying to apply motion blur to rotating fan blades. This will be rendered out as a single frame still image.

The look I'm trying to accomplish is to have the leading edge of each blade be not as blurred as the trailing edge. (like the attached race car image)

Iv'e tried the motion blur in the physical camera and it looks identical to the "camera Effects" version.

Ideas?

Dean

[iadproductions]

Dean,

I don't know if you are a photographer and already know this, the effect your are describing is a very difficult photographic technique that involves precisely timed strobe flashes that go off a fraction before the shutter closes, so the moving object looks sharp.  Also, the sample image you posted I am farily certian is a toy car, and the 'motion blur' is photoshoped.

Now, if you are using mental ray as your render, you can go into the Camera Effects rollout of the Renderer tab and move your Shutter Offset back more, so if your Shutter Duration is .5, make your Offset -.4  so the blur starts nearer the beginning of the fram than the middle.

I hope that helps.

[Pyro777]

Thanks for the reply! I am a photographer 🙂 Yep, you described it perfectly. (Rear curtain sync) Anyway...I'll play with the shutter offset a bit to see if I can create what i'm attempting. The only other way I could think of is to compose 2 images of the fan blades in photoshop.

Thanks for your time!

[iadproductions]

Dean,

I hope the Shutter Offset setting works for you.  I almost suggested rendering in passes and composting the images, but I don't think any of us want to work that hard.  😄

[Pyro777]

LOL, very true!

[Pyro777]

I ended up having two sets of blades. One was stationary and one had motion. Put one infront of the other and render out...worked well.