Cog's Pre-visualization Trick EDIT

(cog) #1

Hi all,

Well stupidly I deleted the original thread when replying to one of the other posts. However, since that was about misunderstanding of what the subject was about I have revised the explanation and also given some background to aid you all.

******************** EDITED **************************

Previsualization is very important in any movie nowadays. Blender has an excellent method of doing a quick screen render or animation using just the blender screen colours via the button on the bottom right of each view window. If you hold CTRL+ a quick animation will be rendered. However, the camera frame frustum will not be shown and if the view has been zoomed out you may get a false impression of what’s in frame or not.

I have therefore come up with a quick and easy solution.

Create a simple plane, oriented to the camera. Scale to the size of the view. Add some extra vertices at the camera frame locations (W sub-divide, move and scale). Then remove the central face (the camera gate). Parent it to the camera and now when you do a previze the framing is shown clearly.

Here’s a simple gif animation to show the difference.

Simple idea but it works.


P.S for further information look for my reply to ScooterL later in the thread.

(dreamsgate) #2

that is one slick trick :wink:

(BrianH) #3

Yeah, I seen this yesterday before you made this post. :wink: I like the concept, maybe we can see a feature like this built in.

** btw, I’m eagerly awaiting your ocean tutorial. I only wish it were sooner then Jan 2006. **

(cog) #4

Hi BrianH,

I know it seems like a long time to the new ocean tutorial, but I want to get it right. I have a list of tutorials planned, with a release shedule, on my website. This was created to kind of force me to complete. When your busy with 3D animation your, very, very, very, busy. :expressionless: :expressionless: :|… :wink:


(sagat) #5

once again you have outdone yourself cog. keep it up

(ScooterL) #6

I have absolutely no idea why you are doing this.

If you want to know what’s in frame and what’s not in frame, why not just switch to Camera view and … you know … see what’s in frame and what isn’t…?

What purpose does this idea of yours serve? Am I totally missing your point?

I’m seriously curious as to what this does that cannot be accomplished by NUMPAD 0 and maybe passepartout…?


(Gnomius) #7

I’m confused too. How is this more effective than just using ALT-A, numpad-0 and the pasepartout button?

(PolygoneUK) #8

For those not ‘getting’ cog’s idea it’s quite simple.

Yes, you can go to a camera IN blender and see what’s in frame, but like cog mentioned, when you render a preview anim AVI, the safe-frame does not show.

So say you were gonna show a small previs scene to someone else maybe through e-mail or a website, and they weren’t a Blender animator, then with cog’s idea the other person would be able to see what’s in frame and comment on the composition of the shot.

At least, that’s what I take it to mean. Is this correct cog? %|

(AndyD) #9

You could even add a transluscent section for the unsafe, in-camera area!

(cog) #10

Hi ScooterL,

Unfortunately you have missed the point so I will try to explain with just a little more information.

There are basically 3 methods of seeing your camera-view animation within Blender.
1 - ALT+A which will, on-the-fly, display the view within the screen. Whilst this method is good for demonstrating extents of animation it gives no idea of actual timing because the speed depends on how much work your CPU has to do to display it. Remember this does not save an animation anywhere it just tries to compute the changes between frames and update the screen. That’s OK for simple objects but becomes slow for any production complex project.
It does however, display the framing Frustum so that you can see the extents of framing as well as the title safe area. As you point out later you can also set the passepartout to darken the frame to make it even clearer.
2 - RENDER and ANIM buttons these will of course render out a still or animation with all textures and lighting as a finished render or animation. This will naturally give the correct framing of the shot but suffers from the fact that renders can take some time. So if you have a 4 second shot with some complex character movements (100 frames even as a small 25% size, with no raytracing, and OSA turned off) may take some time to render.
3 - This button, which is on the bottom right of each view on the blender screen can be used to do a quick screen render or animation (CTRL+ It’s main advantage is that it is very quick as it only uses the screen colours to generate the image. It therefore means that if you want to do a quick animation to check the timing of a movement of your character you can do so without worrying about complex materials or lighting. This technique has been used since the early days of film animation and more recently on live action films.
In a CG type movie, time is the most expensive commodity so finding ways of reducing wasted time is very important. So previsualize often.
Unfortunately, When you use that little button to previze the camera view the frame marker will not show.
That’s why I needed to create a simple way of showing the camera framing using a plane with a few extra vertices and its middle face removed.

Well I hope this makes it clearer for you and others.


(cog) #11

Hi AndyD,

That’s an interesting idea but I don’t think it’s possible yet. Unless you know the method?


(3Dre) #12

In the new blender version, yuo could assign a half-transparent material to it and set Transp on in the draw section :slight_smile:

(cog) #13

Hi 3Dre,

Initially I couldn’t find the settings for this but after a little tour of the new BlenderCVS (2001104) I found it.

Set the material of the frame mask to Alpha 0.5 or less.
With the frame mask sellected press F7 (Object context) and on the draw tab select Transp.

It works a treat, but only in solid view modes, so thanks for the heads up on this 3Dre.


(masterhoshi) #14

Done this before. Funny I did this once before for that very reason. It really is too bad we don’t have a ‘restrict to camera frame’ option for that feature. That way we could actually preview render for test compositing like the big boys.

(Fligh) #15

In 2.4a2 we now have Alt-B


(masterhoshi) #16

What is Alt-B?

(macouno) #17

passepartout in 2.4 alpha 2 in the camera settings.

(Fligh) #18

Read what I said about it here: