Viewer nodes -- Obsolete Tech?

Hey folks,

A few months ago, I was working on a proposal to enhance the workflow in the compositor. I decided against posting it as every time I try something like this, I’m usually met with a little hostility.

In essence, my argument was this:

Using viewer nodes is not a particularly good workflow, because you have to constantly disconnect and reconnect them to get a good idea of what the composite nodes are doing. It’s an annoyance, and it’s messy.

My alternative workflow is this: If you have the ‘backdrop’ option enabled, you should be able to click the node you want to view, and have the results automatically shown in the background. Simple as that.

Shift+clicking two nodes that you want to compare should act the same as the splitviewer node, with a slider on the bottom to determine how much of each node you want to view. This one workflow enhancement would make my node setups much less complex as I could remove all the unnecessary viewer nodes.

So If you decided against it – why are you posting this now?

Because it turns out that Blender already has very similar functionality, but it’s pretty well hidden. I follow development pretty closely, so the chances are that if I don’t know about it, neither do a lot of people.

How it works is this: You can shift+ctrl+click any node you want to view, and as long as you have the ‘backdrop’ option enabled, you can view the results in the background.

If you have a renderlayer with multiple passes (let’s say image, z, and speed) repeatedly shift+ctrl+clicking will cycle through those passes. This is so much faster than having to reconnect viewer nodes to each of the passes to see the results!

This brings up a couple of questions; Doesn’t this pretty amazing functionality make viewer nodes obsolete? and why on earth is something so useful so well hidden to so many people?

I did this a while ago:

It does seem like a good idea, and I’m glad you brought that to my attention, didn’t know, like you said! My old judgement was going to be that if it showed whatever node you were clicking on you wouldn’t be able to check what its doing to a later one, but working like that, where it is a button combo, I don’t see much wrong with that! Thanks! :slight_smile:

wont it trigger many many unnecessary preview renders?

I think that functionality is pretty new…

There are lots of ways to do this… in digital fusion you have two screens to view on and hit 1 or 2 and the active node is displayed on that screen (i may be wrong, it’s been years since I last looked…)
Fast, flexible and elegant!

Nuke has a system with ten outputs…

Personally I think the important thing is being able to compare the current node and another arbitrary node…(but fast switching with less faff would be welcome…

Great counter argument. Yes, you are absolutely correct, and that’s not the only flaw with my original proposal; There are plenty of times where you would want to tweak a particular node, and see the results further down the node chain. That wouldn’t be possible with the method I presented.

No, what I wanted to do with this thread is highlight this new feature that I embarrassingly misunderstood.

I say misunderstood because I’ve just realised that it doesn’t quite work the way I described it. What shift+ctrl+clicking a node seems to do is to connect that node to the nearest (I assume) viewer node…meaning you need at least one viewer node in your scene to get it working anyway.

If you have a node with multiple outputs, repeatedly shift+ctrl+clicking cycles through the outputs, connecting it to the nearest (again, I assume) viewer node. It’s more of a useful shortcut.

I think Freeminds proposal is probably the best solution, with one addendum. If the node has multiple outputs, like a renderlayer node, then Ctrl+clicking the eye icon should cycle between the various passes.

Basically, the gist of this thread is “There has to be a better way”. :wink:

Nah, Freeminds propsal hasn’t been thought through… for comparisons in a split viewer style how do you move the split? Grabbing the mouse modally won’t work as then you can’t edit the node tree… sticking it behind another hidden keyboard shortcut is no feature either… how will people find it?

Also, currently I can use the background in the node editor an/or have a seperate space set to viewer node. this is a Good Thing ™ you can’t get rid of teh “show background” toggle as then you’ll always be stuck with it in your way…

I hate having an unscalable view of the composite obscuring all my nodes… even on a 1920X1200 monitor working in 1080p is too much screen space… Thank gooodness blender is good with multiple monitors now!

For comparisons both Nuke and Fusion have a split node, yet both allow side by side comparison of arbitrary node outputs… This is also a Good Thing™ which in blender you can only get by comparing the composite out to the viewer node out… they also allow setting outputs to be faster than adding a viewer node in blender whilst addressing justin’s concern about automatically following the context triggering too much re-evaluation.

Indeed, more thought is required!

Maybe I’m misunderstanding you, but are you referring to the backdrop image?

‘Alt+v’ and ‘V’ zooms in and out, respectively…but I get the impression you’re probably talking about something else.

Indeed, more thought is required!

Yup…and what’s more, the original poster should have done a little more testing on the feature he was promoting before starting this thread :o:eek:

So it does… Last I asked on blender coders all you could do was pan!

I have felt before that I was hooking up unnecessary viewer nodes, but I didn’t know about ctrl-shift. I just tried it out and that is going to be a huge help for me.

If nothing else,…thanks for bringing this up,… I have a new favorite shortcut!

for comparisons in a split viewer style how do you move the split? Grabbing the mouse modally won’t work as then you can’t edit the node tree…

I don’t really understand this point.

As I stated in the proposal, you just click on the split line and drag it, just like you do on the timeline or gradients.