A Guide to Fusion Expressions - Jake Wipp [ResolveCon '24 - Day 2] (HQ)

[@KaylecNightcore]

We've needed an expressions guide for forever!! Thanks Jake!!

[@chadmullins7553]

Amazing stuff as always! Such an amazing team for every aspect during the resolve con.

[@notrogueking]

this was an amazing intro to expressions, thank you jake and thank you casey!

[@jensgeumann7564]

It's a shame that there are so few good, detailed written manuals for expressions. The Powerpoint is a good place to start for beginners. Thank you for an informative presentation.

[@merlinmerlette]

Coming from After effects, I begin to write expressions for Fusion. This guide is great, thank you ! I would like to have much more like this... variables, lists, text operations etc ;)

[@Alfenium]

Why did you switch? :3

[@TylerProvick]

I got real deep into expressions and found it significantly slowed down my renders. When I asked about it the common response was that expressions are just hugely resource intensive, regardless of how simple you make them. Is that true? I also felt like the people giving me advice weren't really playing with expressions much.

[@christophez3306]

hello Casey, thank you for your work, it's very useful but is there a way so that during the animation with decimal numbers (comma or period, like 1.252, it doesn't move in all directions? I I think it's due to kerning but I don't see how to fix it All the decimal number animation tutorial videos have the same problem, the numbers move during the sequence. It's horrible. Do you have a solution THANK YOU?

[@4Manos]

thanks!!!

[@rossthoughts]

Thought this was a great intro to expressions. But I used to program a bit; I would be reticent to have this be the introduction to expressions for someone that has zero coding background. (With a caveat: I think it is good to watch a video about what is possible - which means it can be more complicated than I can follow - but after that I like to have a slower introduction. I wonder if other people like learning like that?) (EDIT: Came back to say this was a great tutorial to crawl through and actual do what is being taught here. Good shhhhtufff!)

[@ronaldalanis4905]

Yes!!!

[@heathsampson2768]

Great video, thank you @Jake. On this topic I only ever had one Expression: frustration. Now it's joy. *cringe* Thanks for the cheat sheet... @Casey: I love your plane. Did you buy it from the Wright bros?

[@PawFromTheBroons]

That's a very useful and thorough video, but when demonstrating something as detailed and hard to follow as Expressions, please do zoom on them or use a lower screen resolution. I'm watching this on an iPad and I've already paused and pinched to zoom a dozen times, in the first 20 minutes.

[@rossthoughts]

Right! I'm watching on my phone and everything is tiny! (j/k - but seriously though, watch on a bigger monitor ;) )

[@rossthoughts]

Feels logically weird, to me, to use "Text1.Output.Width" to get the width of the composition (eg, 1920, of a 1920 x 1080 composition). Why? Because it feels like it actually ought to return what this returns: "Text1.Output.DataWindow[3] - Text1.Output.DataWindow[1]", that is to say, the width of the text in Text1 node. So I changed the expression to use the code that purposefully gets the width of the composition. (Text1.Output.DataWindow[3] - Text1.Output.DataWindow[1]) / comp:GetPrefs("Comp.FrameFormat.Width") * CustomTool1.NumberIn1 Question: Why does "Text1.Output.Width" return the composition size instead of the actual size of the text1 width? ###### EDIT 1: I copied the working version of the node graph, then pasted a new version of the node graph so I could start experimenting... ...while messing with the Anim Curves on the "X Size" of the transform I changed the expression back to NOT using min( ) so I could see the rectangle grow too wide: time / CustomTool1.NumberIn4 ...only it didn't. Then I became confused. Why wasn't this rectangle growing wider like before? I double and triple checked everything. Nothing seemed to have changed. I suspected Davinci Resolve had cached some values so I closed it down and restarted. But same result: that rectangle wouldn't grow wider as the frame rate went beyond 1.0 (ie, time / custom tool input 4). I then went to the original version of the node graph, the pristine one that I had working exactly as the video had, and I changed that Anim Curves code and removed the "min ( )" from it...and NOW IT TOO had a rectangle that would not keep growing wider as the frames went beyond the set frame rate in the CustomTool1.NumberIn4. Then I found out why. Not that I understand it, mind you, but I found out what was happening. In Anim Curves, if the "Curve" is set to "Easing" then even though the "Input" might indicate numbers great than 1.0 the rectangle will stop getting wider at 1.0. ...the easing setting of the curves is what stops the rectangle from getting wider. lol, it took me 2 hours to figure that out. ##### EDIT 2: I wanted to make the pivot of the rectangle to have an additional option of growing wider from the center. So I added the following logic to the pivot expression that checks to see if the CustomTool is less than zero, equal to zero, or greater than zero. This required a nested IF statement. So here's an example of a nested iif() if someone wants to see how that works: Point(0.5 + iif(cTool1.NumberIn3 < 0, - rBkgr.Width / 2, iif(cTool1.NumberIn3 == 0, 0, rBkgr.Width / 2)), 0.5)

[@JakeWipp]

Hey! Looks like you got most of your questions figured out... For the Text1.Output.Width expression that returns the node resolution, not the composition resolution. If you go to the Image tab and uncheck auto resolution, changing the width will update that expression.

[@rossthoughts]

Ah, ok. Experiment (resulting in a curiosity): node setup: rectangle mask node | to bkgr node | to merge node (merging text node) | to MediaOut node (being viewed). node tweak: text node, Image tab, uncheck auto resolution. expression setup: - rectangle mask node width: (t3.Output.DataWindow[3] - t3.Output.DataWindow[1]) / t3.Output.Width - rectangle mask node height: (t3.Output.DataWindow[4] - t3.Output.DataWindow[2]) / comp:GetPrefs("Comp.FrameFormat.Height") ...for curiosity, not important Perform Experiment 1: On Image tab of text node play with "Width" slider. Oh, that's interesting... the text will shrink and grow but the rectangle does not scale with the change in text size. Interesting. Perform Experiment 2: Return text node's Image Width to default. On "Text" tab of text node manipulate size of text... notice rectangle width grows in proportion to text size. Perform Experiment 3: Go back to text node's Image Width and move slider down about half way, making text much smaller...noting, as before, rectangle does not scale with text width. NOW, return to "Text" tab of text node and manipulate size of text... note the size of the rectangle does exactly scale with the size of the text. DISCOVERIES: A) I now understand what Jake is talking about with regard to the difference between getting the composition frame width and getting the Text.Ouput.Width. B) CURIOSITY: ...I added a text node to monitor this expression: Text.Ouput.DataWindow[3] - Text.Output.DataWindow[1] ...when Text Image Width is decreased by half the monitored expression above changes by about half as well ...however, the rectangle width barely changes at all. That's odd. The text width (as monitored) is changing but the rectangle based on this width is barely changing at all. ...the result of the this experiment is a rectangle that is much wider than the text. ...and now, if we change the "Text" Size - as we do so we see the rectangle exactly mirrors the alteration in text width, as the text grows wider the rectangle grows wider, and visa-versa ...the width of the rectangle appears to based on text size rather than the actual dimensions of the text (as seen with Text.Ouput.DataWindow[3] - Text.Output.DataWindow[1] expression). C) That seems like odd behavior. I'd expect the rectangle width to size with the actual text width without using text size in the calculation.