Disclaimer

Black Dragon is MY Viewer, i decide which feature i want to add and which to remove, i share this Viewer to show the world that user base size is not important, i do rate quality by effort, thought and love put into the project, not some rough estimated numbers. I consider feature requests only if i you can name proper valid reasons i can agree on. It is my (unpaid) time i'm putting into this project, i'm not here to cater to every Joe's desires.

Monday, December 23, 2019

Black Dragon Viewer Guide: #5 Depth of Field

What is it?


Depth of Field is a post processing technique commonly also used in photography where it is a side effect of how the camera is configured to take the picture in question. In 3D rendering it is applied as post processing effect to simulate this effect. It is commonly used to put a certain part of the picture into focus but it can also be used to blur out less good looking parts of the image.

How does it look?




As shown above, Depth of Field blurs the area out of focus, in above's example the focus are the two metal beams in the foreground, right behind them Depth of Field starts to blur, increasing in strength the further it goes back until the configured threshold is reached. In the example above it was used to 'guide' the viewer's focus to the foreground, something out of focus is naturally less interesting to us than something that appears clear, we can use this to put emphasis on something or someone.

How can i use it ?


You can enable Depth of Field by opening 'Preferences' and selecting the 'Display' tab, here you'll find the 'Depth of Field' tab which includes all its options as well.

What can i change?


Just like with real cameras you can configure certain aspects of Depth of Field in rendering, this includes the Field of View, the F-Number, the Focal Length, Circle of Confusion and the Resolution of Depth of Field. In addition you can also customize the time it takes for Depth of Field to switch focus from one focus point to another. Further there are two interesting options to switch between a cheaper but faster Depth of Field calculation and an option to include transparent surfaces into Depth of Field. Especially including transparent surfaces can make a huge difference in how Depth of Field appears.



Caveats


The 'High Quality' Depth of Field is an extremely GPU intensive feature and will quickly drop your framerate if you use a strong blur. It is highly suggested to add Depth of Field at the end of your photography chain as it can make working and finetuning the scene further really annoyingly slow.

Not including alphas into depth can be super useful for Depth of Field, it will make Depth of Field ignore semi transparent particles and stops the 'sudden square blur' that might appear due to this.

Depth of Field stacks badly with Volumetric Lighting, often times Volumetric Lighting will produce 'sharp edges' where objects would otherwise be blurred.

Depth of Field does not scale with resolution, this means that if you take snapshots at higher or lower resolution than your current window you'll have to reconfigure Depth of Field for these resolutions, Depth of Field shares this weird behavior with 'Light Softening', 'Screen Space Reflections' , 'Screen Space Ambient Occlusion' and 'Volumetric Lighting'. Keep this in mind.

7 comments:

  1. The viewer is fantastic, thank you so much! Probably a noob question, but how do you Focus with DoF?

    An RL camera has a focus ring that lets you move the focal plane forward and backward. I can't find anything like this in SL. With the LL & FS viewers I find it almost impossible to focus where I want. I'm not sure why, but it seems easier to have my face in focus with BD. Still, I'm not really clear on how to place the focal plane or how to move it forward or backward from where it is.

    Thank you so much!!

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    1. The focus point by default is placed wherever you zoom onto (like in all Viewers). The other way to move the focus point was always plugging in a controller and activating the flycam which allows you to move the focus point via simply hovering your mouse around. BD adds this hover focus point movement to non-flycam and allows you to lock it (so you can move your mouse freely to go about settings again). Both options can be found in the Dragon - My Useful Features - Shortcuts menu

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  2. The above comment was from me, BTW. For some reason it didn't show my name!

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