CompuServe Thread

Blur

15 messages in this thread
#117449From: John Mateer [PolyMedia]Aug 10, 1994 6:51 AM
I recently got your IPAS #1 disk and am working with Blur. I want to blur an object in the forground while not blurring the background. I've tried using masks but that didn't work (the mask edges show). I also tried rendering the blur seperately and compositing it over the background with the alpha channel – that didn't work either (hard mask edges). How can I do this? I must be missing something… (I'm using 3DSr3) Thanks in advance, John
#117472From: Yost GroupAug 10, 1994 8:55 AM
You're not missing anything. You can blur a foreground object, as long as you don't mind the hard mask edges. Blur is primarily for blurring the entire image and/or the background. 3DSr4 allows for z-buffer-based ixp's to act on the image, so depth-of-field ixp's are now possible. That's what you really are looking for. – G
#117486From: John Mateer [PolyMedia]Aug 10, 1994 9:57 AM
Ah, I was afraid of that. I was a bit confused because the brochure mentioned rack focus effects. How soon will r4 be out? Any idea on upgrade cost? BTW, the flare effects are great. Cheers, John
#117525From: Yost GroupAug 10, 1994 1:50 PM
You _can_ do rack focus effects with it. You can rack either the entire image or just the background, and then composite a foreground over it. R4 will be shipping early this fall. You'll have to contact Autodesk folks for a precise date. – G
#117528From: John Mateer [PolyMedia]Aug 10, 1994 1:56 PM
Thanks for the info. The effects look great! I'm now starting to dive into Disk #6. Cheers, John
#117761From: Jamie Clay [DPh]Aug 11, 1994 11:51 AM
John, don't give up yet, you can do what you want using Blur.ixp with a little extra effort. Yes, you need to render the foreground separately and use ALPHA-Split to build a series of Alpha masks. If you want, you can blur the objects at rendering time, but I always prefer to render all the frames first, blur second – this way if I don't like the blur rate I don't have to re-render the geometry. With the files rendered, proceed to blur the foreground and alpha masks you need for the shot (of course you have to do them separately.) Then use the blurred masks as your Alpha – RGB file for source for the final Video Post composite. It's a little extra work, but it should deliver what you're looking for. Hope this helps, J-me
#117766From: John Mateer [PolyMedia]Aug 11, 1994 11:55 AM
Great. I've got a lot of things to try now. Thanks! Cheers, John
#117618From: David StinnettAug 10, 1994 7:48 PM
You should be able to do this, but it takes a few steps. Blur should have had an option included that would allow it to effect the alpha channel of an image, allowing for a smooth composite, but even though it doesn't, you can still do it manually. First, render your forground object with no background, render alpha ON, and split alpha ON. Once this is rendered, make sure you turn Alpha split off. Then, run your forground image through video post and use Blur on it (Vpost queue will only have your forground image (or an IFL list of frames if you're doing an animation) followed by Blur. This will give you the blurred forground against black. Now repeat the process for the alpha images (because alpha split was ON, they were written to disk as separate images with an "A_" prefix). Now you will have a blurred Alpha image(s) to use as a matte. Now place your background at the top of the queue, then follow it by the blurred forground image. Click in the Alpha slot of the foreground entry and then click on the RGB Mask button, then click in the blank field to the right of it to select the mask. Choose the blurred alpha image that was rendered. Now you're set (you no longer need Blur in the queue). When you render the queue you should get an in-focus background with an out of focus forground object (with soft edges, since the alpha mask was blurred too.) I hope this was what you needed. David
#117660From: John Mateer [PolyMedia]Aug 10, 1994 11:09 PM
I tried it with a test animation and it works great! Thanks a lot! By alternating this technique with the background blur, a true rack focus effect is spot on. Cool. Thanks again for your help. Cheers, John
#117669From: David StinnettAug 11, 1994 12:44 AM
Glad to help. David
#117671From: Yost GroupAug 11, 1994 12:58 AM
Excellent technique, David! – G
#117694From: David StinnettAug 11, 1994 1:59 AM
Thanks. I've had alot of experience with RGB masks lately, its a handy (almost necessary) feature! David
#117754From: Yost GroupAug 11, 1994 11:20 AM
That one ought to be archived for future questions. Jonas? – G
#118506From: Jonas Ruikis [ADESK]Aug 16, 1994 8:31 AM
<< [blur] That one ought to be archived for future questions. Jonas?>> done…Blur.txt in the IPAS Usage section.
#118531From: Yost GroupAug 16, 1994 9:29 AM
Thanks! – G