DOF Idea for RenderMan Support

Blender's renderer and external renderer export

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Pablosbrain
Posts: 356
Joined: Wed Jan 28, 2004 7:39 pm

DOF Idea for RenderMan Support

Postby Pablosbrain » Tue Apr 29, 2003 6:02 pm

I was wondering if there could be a primitive object called DOF or something that would basically be a sphere that you could animate location and scale with and that DOF object would take into account the distance from the active camera to the DOF object. The area encompassed by the DOF object and its scaled size would determine the start and end points on the DOF...

This is just an idea I thought of while working on some other things. I have no idea if this would be easy to implement or not... I am assuming it wouldn't be hard but I have no clue. From a users point of view it would be easy to control... maybe not even a DOF object in the menu... maybe when you enable DOF for your external renderer it would then appear and be accessable for manipulation. I think it would be simple for a new user as well as provide adequate control for advanced users.

green
Posts: 81
Joined: Sun Oct 13, 2002 8:04 pm

Postby green » Thu May 01, 2003 8:41 am

sure :)

I was thinking of using an empty for this.

Ie if I find an empty called DOF in the scene then I check the distance from it to the camera, and can then use that as the center of focus. shouldnt be too hard.

Pablosbrain
Posts: 356
Joined: Wed Jan 28, 2004 7:39 pm

Ah..

Postby Pablosbrain » Thu May 01, 2003 3:47 pm

Once again you are a few steps ahead ... should've known you would have already been thinking about that. Well.. Keep up the fabulous work and I can't wait to see the RenderMan export/functionality working more fully!

beatabix
Posts: 73
Joined: Fri Oct 18, 2002 1:12 am

Postby beatabix » Thu May 01, 2003 8:57 pm

well, as DOF is a focus and aperture simulation effect, wouldn't it be more effective to tie something like this directly into the camera object?

It could work in the same way as the start and end clipping points for the camera -> a vector along the camera's path that can be scaled and positioned.

This could then be used when DOF is eventually added to the blender render.
As most high quality external renderers have a DOF effect, having it built in would be prudent future proofing, don't you think?

later
BEAT

Eric
Posts: 192
Joined: Wed Oct 16, 2002 1:01 pm
Location: Sweden, Norrköping

Postby Eric » Fri May 02, 2003 12:08 pm

beatabix wrote:well, as DOF is a focus and aperture simulation effect, wouldn't it be more effective to tie something like this directly into the camera object?

It could work in the same way as the start and end clipping points for the camera -> a vector along the camera's path that can be scaled and positioned.

This could then be used when DOF is eventually added to the blender render.
As most high quality external renderers have a DOF effect, having it built in would be prudent future proofing, don't you think?

later
BEAT

The problem with the camera changes you're suggesting is that it wouldn't be easy to animate the DOF then. You can do so much more with an empty than you can do with camera settings and perhaps IPO.

Let's just take as example that you want to have a static focuspoint but you want the camera to move.

jmerritt
Posts: 10
Joined: Sat Feb 15, 2003 2:37 am

Postby jmerritt » Sat May 10, 2003 11:02 am

Why not incorporate the empty into the camera somehow, like 3D Studio Max does with targeted cameras?

LukeW
Posts: 64
Joined: Mon Mar 03, 2003 1:14 pm

Postby LukeW » Mon May 12, 2003 3:24 pm

Proper DOF in Blender would be cool!

I like Pablosbrain's idea...

Although having an empty to represent the focus is a lot simpler to implement, I think a circle should be used to represent the focus. It is far easier to see the area that a sphere (shown as a circle) encompasses compared with an empty... an empty is seen as two or three arrows, and a lot of the focus area is behind the arrows. Empties have axis labels and this is irrelevant to DOF. The arrows are useful in showing where the centre of the focus is though, some maybe the focus could be a circle with crosshairs (+). I think that thing should be called the focus rather than an empty called "DOF".

I also agree with beatabix.

Like the option of "ShowLimits" and "ShowMist" there could be the option of "ShowFocus". I think the size of the focus should be able to be changed using the camera properties (like ClipSta and ClipEnd). The distance of the focus centre could also be adjusted there.

Eric wrote:The problem with the camera changes you're suggesting is that it wouldn't be easy to animate the DOF then. You can do so much more with an empty than you can do with camera settings and perhaps IPO.

Let's just take as example that you want to have a static focuspoint but you want the camera to move.

(sorry if this gets hard to understand....)
The camera is always pointed directly at its DOF focus point... at least it is in real-life (I think). Though sometimes the object most in focus can be off centre because nothing at that distance is in the centre, or there is something in front of it.
Maybe you're talking about a camera that is circling a static object which it is focused on. The object would always be in the centre of the screen to have the maximum focus... if the object isn't in the centre, whatever is in the centre (at the right distance) would have the maximum focus (it might be empty space though). I don't think it is realistic for an area to have maximum focus if it isn't in the centre of the screen. (Assuming that empty areas of the screen's middle could be said to be "in focus" and nothing is covering the centre's focus point)
So to be realistic, it seems that the camera needs to be pointed at the DOF focus point....
Anyway, let's say you want the camera to target a static object and circle an object. I think the focus circle should automatically centre on the targeted object...
If you don't want the targeted object to be at the centre of the screen all the time, you could target the camera to an empty near the desired object, then manually move the empty around so that the camera is focused at areas near the desired object rather than directly at the object. Note that this would mean that the object isn't at the maximum focus (if it goes out of the screen's centre) - so then you could increase the focus (add keys to the animation) if necessary. (The focus area, like ClipSta, etc, could be animated.

BTW, if you look at
http://argoslabs.com/~malefico/tutor/dof-en.html
It shows some DOF techniques in blender. All of them involve a DOF empty that the camera tracks. i.e. the place of maximum focus is theoretically in the centre of the screen. I'm not sure about Caronte's method, but with the MBLUR method at least, the centre of the screen where the focal point is would change less so it would have the maximum focus.

So though it might sound good to make the focal point move totally independently from the camera (i.e. so that the camera isn't pointing at it), it isn't realistic and would probably look "fake", and it would mean that the logical camera/dof ideas I was talking about at the start of my post would need to be abandoned...

beatabix
Posts: 73
Joined: Fri Oct 18, 2002 1:12 am

Postby beatabix » Tue May 13, 2003 11:22 am

LukeW -> that's exactly what i mean. i'm thinking more of a camera control widget, built in. Rather than having it track an empty, there would be a track/focus point built in to the camera that could be dragged around, snapped, etc. This could be parented to an object, given an ipo, whatever.

more freedom and control, options etc.
later
BEAT


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