View Full Version : DOF problem

07 July 2003, 10:15 AM
I think I tried every combination but it just won't work. What I want to do is to render two images, one for the rgba and one for z-depth. The z-depth is donne using the surface settings Gradient Distance to Camera. Ok, I rendered both images, tried it with LW and Cinema just to be sure and the images are fine.But it doesn't work, I simply cannot have both layers combined so that I have the rgba as foreground and the-z buffer for the DOF. I'm relly getting insane here, PLEASE, somebody can't be so difficult or can it be???

07 July 2003, 11:51 AM
Hi Philip,

have you tried to render out an RLA image (-sequence)? Should work fine for the 3D effects in DFX+.


07 July 2003, 05:48 PM
You should be able to pipe in your z-buffer info into the FG input (green) on the depth blur node, and set it to any color or luma to get the right effect.

Alternately. Load both your sequences, and set up a channel boolean to combine them.

Be sure to enable the Aux channels, and set the (usually) FG Red, green or blue to the z buffer.

There may also be errors in your DOF if your z-render has any anti-aliasing.

07 July 2003, 08:49 PM
Thanks for your help, I managed to convert the depth file to alpha, invert it and blur through cranking up the luma. I guess my mistake was to think I could tell Depth Blur that the blur image would we in the z channel.

By using the channel boolean I was able to put the depth file into the z channel, but it looked broken. I tried with no AA, Greyfile, 256 tones, tif, tga but it still looked broken, any idea??

With RLA I have the z channel set correctly, but it's only one grey, and has no white to black gradient like it should, I tried different DOF ranges, but nothing changes?? Funny.

BTW Andreas, I left Pixelspell and Tom's quite angray now, it really was a neverending story...

07 July 2003, 09:30 PM
I'm not too sure what lightwave is doing or not doing. If you have a very narrow camera range the image can be a constant grey, but may have information there. You can sometime pull this information out by using the z-scale slider in the depth blur tool. Without the actual images, I can't really say what might be going wrong.

07 July 2003, 10:22 PM
I finally got it :applause:

Rendering as RPF works, RLA seems not to produce a depth, it remains blacks. I tried a simple scene with 3 ball, and as RPF I could now really see the diefference in the gradients. I retried my old object where everything looked one grey and noticed at the bottom the different z values, easy isn't it :) but I had to use very subtle values to see the effect. I set Z scale at 0, the blur size at 5.7 the focal point was only -0,4633 DOF was 0 too. With these settings I had a great DOF Blur. If i made DOF and Z scale just as much as a little above 0 the effect was gonne.
Dear or dear, that was a tough one, I very much appreciated your help, thanks.

I you could also tell me why converting an external z file to a z channel always produces wrong results I would be extremely grateful. adaptive sampling was always off, and AA too. Please check the image. On the left side you the rgb of the z file and on the right side the created z channel.

07 July 2003, 10:59 PM
Well I haven't talked this over with the deveopers in some time, but I recall this is correct. It's because the z-channel is floating point. Each of those white to black bands is calculated with a multiplier, to get the correct results.

You can try to toggle the "show full color range" on the display to see if it shows it as you might expect. (I can't recall if this will flatten the bands or not)

All your tools should work as expected after the boolean though.

07 July 2003, 11:22 PM
Yep, you're right, it looks bad but it works fine, even better than rpf since it has more contrast and I can exactly determine the range of the gradient. The drawback I have to save a second set of objects, and change all surfaces (this is donne rather quick, though)
Fine, now I have two methods to do DOF, I'll just have to inquire why RLA doesn't save the z-buffer or is it DFX that doesn't read it??

You helped me a great deal Jayk2k, thank you very much :beer:

07 July 2003, 11:48 PM
I know each application saves it's RLA and RPF files slightly different. The developers at eyeon try hard to maintain as much compatibility as possible, so it's most likely Lightwave, but I could be wrong.

Justin W
07 July 2003, 01:44 AM
Hi Philip,

If you render out a "Deluxe" RLA from the render options, you're right, the Z doesn't seem to work. The "Extended" RLA in the Image Filter queue seems to work fine. An easy way to get the right focal point (without using the slider) is the "pick" button. Click & hold while you drag across the image, you wil get near realtime visual updates of exactly where the FP is.


Justin W.

07 July 2003, 08:46 AM
"Extended RLA" works fine, thanks, I tried so many things, also extended, don't know why I overlooked the z channel?? The pick button is really great, don't know why but RAL/RPF always give me minus values for the pick point. Do you know how to change the gradient range for the z depth in LW, I mean how do I tell LW how big the world is??

BTW Philipp with two p at the end not Philip ;)

Justin W
07 July 2003, 01:58 PM
Hi Philipp,

I just tried this, works great. Render options - RGB set to Deluxe RLA (I just figured out how to get the Z to work!!!). Image Process - Deluxe RLA export (not extended RLA). The properties for Deluxe RLA will allow you to get a 32 bit Z buffer (as well as changing the bits for RGB and Matte). This appears to give the results you are looking for.


Justin W.

07 July 2003, 03:30 PM
Yes, you're right, color/matte as 8/16/FP works, z as FP, the z channel shows black but it's there, it has the range from 0 to 1.

That's cool, many possibilities one has :drool:

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