🚀 go-pugleaf

andy@crazybe.demon.co.uk (Andrew Barnett) writes:

>Hi All, just a silly little question

>I'm trying to do an effect I saw in a car advert poster, the car it self
>was not blured but the wheels were as it was speeding along. Who do I get
>the wheels to blur but not the whole car/ picture ?

>The answer is probably staring me in the face but I can't see it.

There  may be an easier way to do this but something  along  this
line may work -

1] Set up your scene with the car motions/background etc.

2] Remove everything but the background and render without mblur.
3] Load   the   scene again,remove all excpet wheels render with
mblur
3]  Load all again remove everything except the car  body  render
without mblur.

Now  in AdPro compose the three sets of frame sequences  and  you
should have something that works.

Alternatively  you  could experiment with foreground/background  image
options  to compose the frames in one pass.

Anybody else want to help out, there must be an easier way to  do
this :)

GVN
--
Spoo!

Andrew Barnett wrote:
> 
> Hi All, just a silly little question
> 
> I'm trying to do an effect I saw in a car advert poster, the car it 
self
> was not blured but the wheels were as it was speeding along. Who do I 
get
> the wheels to blur but not the whole car/ picture ?
> 
> The answer is probably staring me in the face but I can't see it.
> 

How about this...target the camera to the car, so that the car's
motion in the frame is fixed.  Rotate the wheels, move the car,
and oila!  when you apply motion blur, you car should be fairly
stable, with blurry wheels and background.
---Prem

andy@crazybe.demon.co.uk (Andrew Barnett) wrote:

>Hi All, just a silly little question

>I'm trying to do an effect I saw in a car advert poster, the car it self
>was not blured but the wheels were as it was speeding along. Who do I get
>the wheels to blur but not the whole car/ picture ?

Set up your scene: car ,wheels and everything else, as you would
normally.  Render the car first without the wheels (or the wheels set
at 100 percent transparency) then re-render the scene with the wheels
only and motion blur on. The trick is to save alphas when rendering
the wheels, then composite them with the original. Also, if some of
the wheels are being occluded by the car or other objects, make sure
you include those objects when rendering the wheels but set their
surface attributes to:
	color = black as black can be 
	luminosity =100 percent
	Diffuse = 0 percent
This will effectively matte out the background wheels, 
(hopefully) achieving the effect you want. I haven't tried doing this
but it should work assuming the motion blur effect is saved with the
alphas.

steve gowin wrote:
> 
> andy@crazybe.demon.co.uk (Andrew Barnett) wrote:
> 
> >Hi All, just a silly little question
> 
> >I'm trying to do an effect I saw in a car advert poster, the car it 
self
> >was not blured but the wheels were as it was speeding along. Who do 
I get
> >the wheels to blur but not the whole car/ picture ?
> 
> Set up your scene: car ,wheels and everything else, as you would
> normally.  Render the car first without the wheels (or the wheels set
> at 100 percent transparency) then re-render the scene with the wheels
> only and motion blur on. The trick is to save alphas when rendering
> the wheels, then composite them with the original. Also, if some of
> the wheels are being occluded by the car or other objects, make sure
> you include those objects when rendering the wheels but set their
> surface attributes to:
>         color = black as black can be
>         luminosity =100 percent
>         Diffuse = 0 percent
> This will effectively matte out the background wheels,
> (hopefully) achieving the effect you want. I haven't tried doing this
> but it should work assuming the motion blur effect is saved with the
> alphas.

Hello!  Folks, it doesn't need to be this hard.  Photographic
sequences where the moving subject is still wrt the frame and
the background/wheels/etc. blur are done where the photographer
tracks the object with the camera and then snaps the picture.
Because the camera is tracking to the object, it remains still
wrt the frame of the picture.  The background will blur because
the camera is panning against the background while following the
object.  The wheels will blur because they're moving.

Soooo, do the following:


1. Set up a scene with a car, a background image mapped onto an
object, a road in the foreground, and a car on the road.

2. animate the car moving through the scene, rotating the wheels
by however fast they need to go (roughly) to rotate for the car's
movement.

3. target the camera to the car.

4. render a frame where the motion of the car is essentially
perpendicular to the line drawn from the camera to the car.  If
the car's movement is not perpendicular, there will be some slight
perceived rotation and some minor blurring to the car.

IT'S JUST THAT SIMPLE!!!

---Prem
perpendicular

andy@crazybe.demon.co.uk (Andrew Barnett) writes:

>Hi All, just a silly little question

>I'm trying to do an effect I saw in a car advert poster, the car it self
>was not blured but the wheels were as it was speeding along. Who do I get
>the wheels to blur but not the whole car/ picture ?

>The answer is probably staring me in the face but I can't see it.


><sb>
>Nuff said, 
>                              Andrew Barnett
>                 +--------------------------------------+
>   _   _____  o  | A4k30fp, 18Mb, 760HD, LightWave 3.5, |  o  _____   _
>  | \_/    *\  o |   Forge 1.0, Essence 2, Ilyama 17"   | o  /*    \_/ |                    
>  |  _  PGP  ]o  |        CyberVision 64 (4Mb).         |  o[ 2.6ui _  |
>  `-' `-----'	 |UK Moderator of LightWave FidoNet Echo|    `-----' `-'      
>                 |       andy@crazybe.demon.co.uk       | 
>                 +--------------------------------------+
>                      .....CrAzY Bee Productions.....
><sb>
>"Apparently, non-human minds can cause a problem for someone who isn't trained."
>'Yes, I *have* heard this.  We do not all think the same way.'
>-- Ivanova and Delenn, "Legacies"

Yep, you're right - it should be easy...

	Firstly, set up everything as you would normally to render the car, but
make sure the wheels are separate objects.  Then the trick would be to keep the
car still and make the wheels move into position at a high speed (spinning if
you want them to).  Now render the frame where the wheels have just caught up to
the position they should be in under the car and you're done!

	Not hard was it? :)
--
************************************************
*  Leon Blackwell                              *   o   o
*  A1200, double speed '020, 4M fast, 540M HD  *     |
*  blackwel@cs.curtin.edu.au                   *   \___/
************************************************

	Hi Andrew....

	I'll make a couple of assumptions here...

	1 - That you are attempting to _animate_ and not simply
	    do a single frame.

	2 - That your reason for asking about blurring only parts
	    of the car (wheels) is to reduce render time.


	If this is correct, the answer is simple.  Do what I did to
	get blur _before_ motion blur was included with LW.

	Turn off motion blur.

	Replace the wheels with a new set of wheels that have no detail,
	only smooth surfaces for the wheel/hub.

	Paint an image map of a wheel that looks blured (image processors
	can help, and if need be, render a single image of your original
	wheel in lightwave, with motion blur on and the wheel in rotation,
	save the image).

	Map the image to each wheel.

	Render normally.

	-mp-