Maybe this tutorial will help you as a starting point.
https://www.youtube.com/watch?v=6Kj8HFEBcTA
@gnomalab I have gone through all those tutorials; thank you anyway. That is a manual way of doing feedback. TD has a node Feedback, but I don’t seem to find any parameters to change its behaviour.
Hi again,
I have managed to customize and publish the parameter but still struggling with the Render size ones, its to say, I dont know how to 'connect/relate the Parametr node to the Comp node.
In the Comp node I go to Common tab, switch from Use input to Custom resolution and then drag the Parameter node over to Resolution field but it comes up in red with no Rendersize published.
I can see the in the provided example tox. in vdmx it always says:
op(‘par1’)[‘Rendersizew’]
op(‘par1’)['Rendersizeh’]
Even when I write this manually and then load the saved .tox file into vdmx I still get the message: the project doesn’t have the requiredinputs and outputs. Would anybode know how to proceed?
Thanks for any help!
1 Like
Hello - the feedback node by itself doesn’t do anything - you have to make it part of a feedback loop for an effect to happen. And then you play with parameters of other nodes (eg blur, transform scale or rotation etc) placed inside that loop, to effect your imagery.
This tutorial explains it well.
“Feedback loops are amazing yet always seem elusive for TouchDesigner artists. How do we make them? How do we control them? How did adding a single random operator create this amazing effect? Unless you understand the fundamental way feedback loops work in TouchDesigner, you’ll always be guessing. Lucky for us, Elburz dives into the mindset and essence of feedback loops in TouchDesigner and how to unlock your full creativity with them.”
Hello @id_mora - I’m only a TD beginner too - but I think you’re adding an unnecessary complication… ie - you only need to publish parameters that you might want to adjust with a slider later - eg a blur effect…
The render related parameters arent for publishing as sliders to be controlled later, they’re passed to VDMX to determine the resolution.
If you open up the vidvox supplied Image_Input example…
(› Application Support › VDMX › TouchDesignerFX › TDIO_Image_Input.tox )
You can see some explanation (select the image input operator + click i to go inside it… )
My experiments have been with saving the example files under new names, and adding parameters for other things (eg blur). Ive just left the render resolution parameters alone, and that has worked fine…
@jeanpoole thank you this is very helpful. I think I get the jist a bit more. So then the feedback loop draws for every frame? I guess that part of it can’t be controlled. The echotrace effect that I have created works just fine, I was kind of hoping to have some fine control on the frequency of the feedback.
Here is an example of the echotrace so far:
I was wondering if there is a way to make those “frames” more often
1 Like
The key for feedback loops in TD (says me, a beginner 
), seems to be what you do inside your feedback loop - ie in between your feedback node and your output… (which could be adjusting scale / position / blur / levels etc - to get all sorts of effects over time… changing those values will make each new ‘frame’ appear closer or further etc… )
Have a look at the motion trails part of this feedback tutorial, I think it might help you understand how to adjust feedback the way you want…
PS - As suggested by @gnomalab earlier, an alternative to the ‘feedback node’, is using the ‘cache top’, which is a technique suiting clips with alpha channels, but lets you easily control how many replications you want… (aka this tutorial )
And yeah I guess playing around with various keying effects, or finding edges, of a full screen video, will help isolate areas for trails within feedback loops…
Hi @jeanpoole , thanks for your help. I know the related parameters aren’t for publishing as sliders, buttons, etc. Like I said, I just don’t know hot connect them to the Comp node.
In your screenshot the Parameter window is connected to the Comp window with that straight thin line with an arrow in the middle, there is a reference between the too. What I’m struggling with is that connection. In my video you can see the Parameter window has no reference to the Comp and when I try to drag it over the resolution field, it comes up in red color.
Its probably a basic thing to do, but I can’t figure it out.
Thank you
@jeanpoole I understand how the feedback node operates and that you can adjust some of its behaviour through additional nodes. Unfortunately, all you can do is affect each instance of the feedback, and you can’t really affect how many instances the feedback node produces or how often they happen - these are the fine adjustments I was hoping I could address.
I have seen the trails tutorial you linked and have actually started out with the cache nodes but have quickly given up because I don’t know how and if you can iterate inside TD. If I could create something similar to the “build a list” in VUO, where I can change the size of the list based on other parameters, then that would actually do what I want.
Put simply, I would want to affect how many of the trails are there and how often they are imprinted.
Hello @id_mora -
Have you tried copying the supplied vidvox touch file, with working output, saving as a new name, and integrating your TD constructions inside that?
That should work…
I’m still learning TD atm, and did the above, as a brief test / ‘proof of concept’ to see if i could get a TD edit exposing parameters for playing inside VDMX…
That worked for me, but now I’m back to working my way through learning more TD before trying to build anything else for vdmx…
Re: your problem tho -
Open up the vidvox image input example,
Click on the comp - you’ll see in the comp’s parameter window that the rendersize width + height references data from the ‘par1’ CHOP.
You can add those scripts, or click the + of par1, to make the data sliders available for dragging and dropping onto the resolution width+height
Within minutes 8-10 here - Trails & Frame Delays: TouchDesigner Tutorial 041
they specifically go over how to add X number of frames (in their case, iterating X number of banana graphics)
One last feedback link - how cute is NOTO THE TALKING BALL?
What is feedback? feedback in Touchdesigner (터치디자이너 튜토리얼 자막)
Maybe I am not explaining myself well. Iterating with a known factor of times is indeed doable and simple. What I would like to achieve is having control on how many iterations are there, while the compostion is running. So that you could change the number of iterations with a slider. You could maybe do like 5-100 nodes and switch them on and off, but that is not the itertive way of doing it. The solution would be to have a node that can copy an operation several time, while changing some parameters. In the trails example you would have only one of the selectframe nodes, which would then in turn be repeated and modified by another node. Quartz Composer had pretty simple iteration and Vuo has decent iterative options. IDK about TD, though.
The second video with the NOTO the talking ball is indeed super cute! And great resource. I think I am starting to understand where the issues with the feedback and video lies. And I believe the problem is with the framerate of the specific video. I was searching for a way to change that inside a compostion, but the only frame changes I have found is the same as in this tutorial. Basically changeing the FPS of the compostion instead of manupulating the framerate of the video.