#Scene Motion Blur
13 messages in this thread
I'm having a few problems with Scene Motion Blur, so I have created a simple
scene to find out what I'm doing wrong. I have created a box and then on frame
10 had it move to left some distance away. I've left the default settings for
Scene Motion Blur, i.e. 50% dither in Render/Setup/Options and selected Scene
Motion Blur with it's setting of 5. I put a white solid colour in the first
entry in the Video Post then the KF scene in the second entry. I then went to
frame 10, the final position, and requested Render then Single. When the image
is rendered, the renderer renders the scene 5 times as expected, the resulting
scene shows no blur simply the box in it's final position.
What am I doing wrong. As I understand it the Renderer will render the previous
5 frames from the current frame, in my case the tenth, then compose them all
into the final image dithered at 50%. Am I missing something?
Thanks.
Hi David,
<< When the image is rendered, the renderer renders the scene 5 times as
expected, the resulting scene shows no blur simply the box in it's final
position.
What am I doing wrong. >>
Scene motion blur is based on the movement of the camera with respect to your
scene. If your camera
isn't moving, you won't notice the effect. I like to use selective object
motion blur instead of scene motion blur for many of my character motion tests.
jonas[adesk]
Thanks for your response. I am starting to be very confused. You said that
Scene Motion Blur will only blur objects if the CAMERA is moving and not if the
objects are moving. Well in my case the camera is stationary. But when I read
the reference manual p8-137 section Scene Motion Blur "Scene motion Blur is a
time-sensitive special effect that creates trails behind ALL moving objects
…" also on page 7-207 section Scene Motion Blur ". The second(scene motion
blur) applies motion blur to the entire scene. Any movement within the
frame-EITHER by camera movement or object movement, is affected."
It is therefore my understanding that Scene Motion Blur should blur moving
objects irrespective of whether the camera moves. Yes I have tried Object
Motion Blur but the results did correspond to my needs. In the example I gave,
I want a blurred trail behind the box and then have the box rendered as it
would be normally, i.e. solid box. But what I end up with is some spotty
transparent copies of the box behind a half transparent box. Obviously I could
snapshot the final position of the box and not assign any motion blur to this
object this gets around the problem of the box looking transparent, but what do
I do to improve the 'streak' rather than 'slodges' of colours I want as the
motion blur.
Thanks.
Scene Motion Blur is simply a way of compositing multiple sub-frame images
within a single frame. If you've got sub-frame motion, then it'll do the
composite (whether or not the camera is moving). It's best used along with
Object Motion Blur, judiciously (on objects that'll later be composited into
other, more complex, scenes. If you've having a problem using it, I'm sure
that Jonas, Brian or Nik would be happy to take a look at your file and point
you in the right direction.
– G
<<Scene Motion Blur is simply a way of compositing multiple sub-frame images
within a single frame. If you've got sub-frame motion, then it'll do the
composite (whether or not the camera is moving)…>>
Sorry but I'm not up to date on the terminology. What is a 'sub-frame image'
and 'sub-frame motion'?
Thanks!
Sorry for the arcane terminology. If there's motion between the current frame
and the NEXT frame (like Steven described), then there's motion between the
frames (ie, sub-frame). That's why you won't see any SMB on the last frame of
an animation (it has effectively stopped on that frame).
– G
Hi David,
You are doing nothing wrong, it's just a slight misunderstanding about how
scene motion blur works.
Scene motion blur applies the number of copies from your current frame
forward to the following frame. In essence, scene motion blur extends into
the future to blur the object into its next position.
It sounds as if frame 10 is the terminal frame for the box (it moves from 0
to 10 and then stands still). The test rendering on frame 10 is applying
motion blur to the box based upon its postitions at frame 10 and 11. Since it
does not move between those frames, there is no blur. Try your test rendering
at frame 5 instead and you should see the blur effect in action.
There is a discussion both object motion blur and scene motion blur in
Chapter 20 of "Inside 3D Studio".
Steven
<<Scene motion blur applies the number of copies from your current frame
forward to the following frame. In essence, scene motion blur extends into
the future to blur the object into its next position.>>
Is that accurate from a realistic standpoint. 'In the real world' doesn't the
blurred streaks follow the object rather than move ahead of it. Object Motion
Blur produces streaks behind the object(where is was previously) but the Scene
Motion Blur produces streaks in front of the object(where it is about to go). I
can conceptually understand the Object Motion Blur but why does the Scene
Motion Blur produce streaks into the future. But in the reference manual p
8-137 under the secion "Scene Motion Blur" it is written "…that creates
trails BEHIND all moving objects…". Why then are the trails in front of the
object on a given frame. Surely the given frame of an image won't include
things that are GOING to happen but rather things that HAVE happened. It seems
counter intuitive, I must be missing something.
The purpose of all this is to create a single still image with a text object
that show a streak behind it. The text object flys around a sphere. I want the
final image to show the text object in it's final position rendered normally(no
transparency, no blurring) but behind the text object I want a streak or trail
showing the motion blur. How can I achieve this effect?
<<There is a discussion both object motion blur and scene motion blur in
Chapter 20 of "Inside 3D Studio".>>
Unfortunately I don't have this book. Since I'm in France I don't think I can
get access to this book here. Could you please tell me where I can get book in
America. Its unfortunate that non of the tutorials included any information
about motion blur.
Thanks!
David,
You can call 317-581-3500 and ask for the New Riders Publishing order
department. We'll ship anywhere in the world.
____kevin
<<You can call 317-581-3500 and ask for the New Riders Publishing order
department. We'll ship anywhere in the world.>>
Could you send the information about ordering to me by e-mail, I can then fax
the order through directly. I want to buy the books "Inside 3D Studio" and "3D
Studio Special Effects".
>> Could you send the information about ordering to me by e-mail, I
can then fax the order through directly. I want to buy the books
"Inside 3D Studio" and "3D Studio Special Effects". <<
Fax the order to +13175814675, with your name, address, CC #, and the
description of the books you want.
>> Could you send the information about ordering to me by e-mail, I
can then fax the order through directly. I want to buy the books
"Inside 3D Studio" and "3D Studio Special Effects". <<
Fax the order to +13175814675, with your name, address, CC #, and the
description of the books you want.
Steve
Are you sending CIS from a truck in the Rockies<BG>???? If the rumors I've
heard are correct, then congradulations!
TedB
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