Hi all,
I was wondering if blender can have a value output box or window in the math nodes or in all the nodes that we need to know the value which is about to be …
i faced this difficulty few days back, i needed to know the out put value of some math.
regards
You’re assuming that math nodes put out a value that could be expressed by a single node, but that’s rarely the case. A math mode can output a completely different value for each pixel, or object surface point, or texture coordinate, or incoming light vector, or any countless other number of things you can input and output from a math noise. Additionally, the output of some math nodes isn’t even known until the result is Monte Carlo sampled and averaged. There’s no possible way to output any meaningful value to a simple node that would express anything in a more useful way than a simple emission shader with an intensity of 1.
It would still be useful to have such a node, even if we have to supply its driving output manually, be it float, color, or vector.
So, adjustable mode and driving output connector, and a feedback node input that allows the node to show the result of the calculation.
The wiring might look weird, but it’s something we would use for debugging other nodes. I made a atan2 setup that failed miserably, and would also show near the “zero edge”. Such a node would have proven extremely helpful to debug what was actually going on.
I have thought about this too and my idea is about not having a node to output the values but simply having the values pop up while holding your cursor over the node link (maybe pressing some button like shift).
There could also be an option to enable these boxes to constantly show for all node links.
While this probably wouldn’t commonly be used I’m sure it would be a life-saver sometimes.
And about that output values rarely are a single value that could be solved by having the interval of these values shown instead. For instance say I have a grayscale texture with values ranging from 0 to 1 (white to black). If I were to show the value of it I would get the simple intervall “0-1”. 
If I then were to multiply it with 0.5 I would get the interval “0-0.5” and so forth.
you still need to render to see values!
might make render size like 10 X 10 and get 100 values to evaluate and see results
happy cl
Well, that already goes for all sorts of previewing in the compositor so nothing new there 
Also the material/texture editor could show values without the need to render.
I think what might be more useful than simply having a value output would be a viewer node like what we have in the compositor (so we can have Cycles render a preview of the material at that point where the node is connected (and then perhaps have a background preview image that changes depending on which viewer node is selected, either that or we just change the preview in the properties panel).
While a material output would be a godsend it serves another purpose than a value output, so the need for it is still there.
Some data is possible to show. Like textures. It would be nice to be able to preview the look of textures in the node graph. Like a viewer node.
For other values maybe a generic data node?
Showing whatever data no matter which kind it is?
My idea is that the viewer node would be able to output a preview of whatever is connected to it.
For instance, if it was connected to a branch of the tree that did not contain any shader nodes, it would output a color or greyscale-based snapshot instead.
Though I guess you want to know exact values (such as 2.198 or something), I have the idea that the viewer node system can also pass values to Blender’s eyedropper tool so you can see the exact numbers if needed.
I would love to have a node that shows a floating number value result. This is something that would come in handy for debugging.
Now this was probably overkill, but I just felt for making a little demonstration of how I think it could work:
https://drive.google.com/file/d/0B8I7vdW7EC1iUjZvUVNvbVpvWVk/view?usp=sharing
^Note that the value of the gradient texture is shown as 0.0-1.0 since it conctain a variety of colorvalues ranging from black to white.
@Ace Dragon, I’m very much for a material preview, but I think a value output would work more efficiently as it’s own feature.
just do ctrl B create a small brender; oops Blender render 
and hit the left mouse button klick on the image parts your intrested in.
You might render using the input not a render scene for this but a texture / color pattern
I tried to sample the 3d preview output with the eyedropper of a RGB input node but it clamps everything to 0-1, and also it’s not precise: a math node set to add 0.4+0.5 gave me 0.905 R, G and B each. And 0.896 sampling in the material preview panel.
Having R-G-B values in viewport-rendering mode would solve many of these needs. You would be able to preview the graph at any point (node-wrangler addon then Ctrl-Shift+Click on any node) and hover in the 3d window to see numeric values, as you do now in uv/image editor with right click. It’d prevent also values shifting due to color management (exposition <> than 0)
would it not be precize, or would it be that rendering has more effects then we think it has ?
thanks a lot for all your valuable participation, i totally under stand the issue about the output variety that can be out of the math node.
to make simpler … i wanted to know the value of dividing the " particles age and life "
and some values in another file for a value powered by another input !!
i am not talking about textures and materials and RGB data … it is simple math only
and just to add to it " what if you clamped the value in the next node so what is value going to be ? "
i hope you got my point
regards
it looks nice … but i think a node ( similar to the view node ) or maybe the mathmatical value to be written on the top right corner of the node it self maybe …
but yes this is close to what i was asking for … many thanks
Two modes (checkboxes) for the viewer node would be nice:
In addition, maybe min/max sliders where you can drive a normalisation. I.e. after measure I find values are between -10 and -2, if I plug these values in I can read out the normalised value of 0-1 range instead. Makes it easy to obtain values for a normalisation process. Important if using Musgrave texture to drive color. I have my own node group for this normalisation process now, but probably something many would have a hard time with.
If some form of value viewing were implemented however limited this is an example I’ve found useful.
9 minutes onward.
