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So, I was trying to replicate this tutorial: https://youtu.be/9AV_ikY_Gss

As usual I never seem to be able to replicate what is being done. In this case I have 2 problems.

Problem 1: Particle size: At 13:32 in the video, he presses the play button and gets tiny particles generated around the text. When I do the same thing with the same settings, mine look like giant soap bubbles wrapping around the text rather than tiny particles.

Problem 2: After setting up my brush and my canvas, I try to bake but nothing happens. At 15:16 in the video, he bakes his dynamic paint setup and the text becomes blue as it happens. Nothing happens for me.

I have searched high and low for solutions to these problems but cannot find anything that matches what the author of the video produces.

Any ideas are welcome, thanks.

Blender file link: https://www.dropbox.com/s/gkv5iku35tat7ei/Sporcul_Burn_03.blend?dl=0

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  • $\begingroup$ The tutorial uses Blender 2.79. A few things may have changed and there are some old known bugs in Blender 2.8+ regarding particles and Dynamic Paint. Problem 1: the halos that you see in the viewport are just for visualization. It's just used in the viewport, not for render. Don't worry about the size. This is the default size in Blender 2.8 and higher. On the Particle Properties tab you can change the Viewport Display > Size to make them smaller or even look different. $\endgroup$
    – Blunder
    Mar 5, 2022 at 21:06
  • $\begingroup$ Problem 2: You need to create the vertex colors for the Dynamic Paint (DP). Unfortunately, the output section is collapsed by default & you don't see the error (red field) => blender.stackexchange.com/questions/157056/…. But even if you do this it won't work in Blender 3.0. Don't know why. It seems that a DP brush (particles) + a DP canvas on the same object don't work for some reason (bug?). Workaround: duplicate the text object and use one as Canvas (remove particles+brush) & the other as Brush (with particles, remove canvas) $\endgroup$
    – Blunder
    Mar 5, 2022 at 21:18
  • $\begingroup$ On the Particle Settings tab, in the section Render and Viewport Display you can hide the emitter object (the text) so it's not rendered twice. Or disable it in the outline (camera icon). $\endgroup$
    – Blunder
    Mar 5, 2022 at 21:19
  • $\begingroup$ Dear Blunder, thank you for taking the time to look at my problems and helping me out, it is very much appreciated. All your answers make sense to me. Given that I am a beginner user I do not know the history of Blender including the known issues so your comments are so helpful. I am using the last stable version of Blender which is 2.93.8 . Regarding the DP problem I guess I could revert back to 2.79 to do the project or try to use your suggestion of a duplicate object. Finally I found the "Show Emitter" tick marks where you told me to look. Thanks again so much, you rock! $\endgroup$
    – JG1XMV
    Mar 6, 2022 at 8:47
  • $\begingroup$ Hi. I would stick with the latest stable Blender version (right now 3.0 but 3.1 will be released soon). The 2.93.8 LTS version is the long-term support version of the 2.9 build. It gets bugfixes for 2 years but no new features/changes. 3.0 has Geometry Nodes Fields (GN 3.0) which is a complete revamp of the 2.9 GN. Blender 2.8 also was a huge update. Most of the old tutorials work in 2.8+. The main change was the GUI/appearance and shader nodes. The problem you encountered is a "feature" that is no longer supported in 2.8. Text duplication works fine (see answer below). Hope this helps :-) $\endgroup$
    – Blunder
    Mar 6, 2022 at 15:55

1 Answer 1

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The tutorial uses Blender 2.79. With Blender 2.8 came a big update and some things may have changed or might no longer work as they did. There are still a few old known bugs in Blender 2.8 regarding particles and Dynamic Paint (such as update problems).

Let's start with the real problem first.

Problem 2 "Particles don't paint Dynamic Paint" - no longer supported in 2.8+

In your project, the text object is used as Canvas and Brush at the same time. This is no longer supported in Blender 2.8 and higher. See bug report T64149 -Regression in dynamic paint, blender 2.8: cannot make an object act as canvas and a brush simultaneously. Quote:

We do not support this in 2.8. Having the object be both a canvas and a brush at the same time could lead to very bad dependency cycles. So not we made it so that an object can only be either or (as implied by the GUI in 2.79 and 2.8).

If you try this in Blender 2.8 then Dynamic Paint is just disabled and you only see the manually painted vertex paint (white by default).

Workaround

  • create a linked duplicate (Alt+D in Object mode) of the Text object. Then both objects share the same mesh data so you don't have to worry they could be different.
  • make one object a Canvas and remove the Brush in the Dynamic Paint settings. Also, remove the Particle System from it.
  • make the other one a Brush, remove the Canvas and keep the particles.
  • on the Particle Settings tab, in the section Render and Viewport Display hide the emitter object (the Text (Brush) object) by unchecking [_] Show Emitter so it's not rendered twice (see 2nd screenshot below). Otherwise, you get shading issues and it covers & hides the canvas → big confusion!
  • for the Text (Canvas) object you need to create the vertex groups dp_paintmap and dp_wetmap for the Dynamic Paint: vertex groups for DP
    See Dynamic paint does not work on canvas in paint mode for details. By default, the section is collapsed and you don't see the red field that indicates the missing vertex groups (error).

If you want to see the Dynamic Paint for a burn effect or just to check if it's working you can use the Vertex Color node in the Shader Editor:

enter image description here

Problem 1 "Different Halo Size" - not a problem

Don't worry about the Halo size. The halos that you see in the viewport are just for visualization. This appearance is just used in the viewport, not for render. Halos are probably a leftover and not even rendered in Blender 2.8+.

You can change the appearance of the particles in the settings for the rendered image and for the Viewport Display individually.

If you want to have smaller or bigger halos in the viewport just change the Particle Properties > Viewport Display > Size value.

If you want to render the particles, set Particle Properties > Render > Render As to Object and choose an object.

particle appearance settings

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  • $\begingroup$ Hello, I have updated to 3.0.1. I have redone the project from scratch using your instructions. I could be missing something obvious since I am a beginner, I think that I am getting close but I get no joy getting the burn effect that you get when I play the animation. All the information you provided was super useful, I have learned a lot, but I think I just need one last effort to get over the hump. Your image of the logo getting burnt looks awesome. Any chance you could have a look (if I may)? dropbox.com/s/3zawarl74fj8kyc/Sporcul_Burn_Blunder01.blend?dl=0 $\endgroup$
    – JG1XMV
    Mar 7, 2022 at 9:54
  • $\begingroup$ Hi. Great work :-) The burn effect (Dynamic Paint) doesn't show right now for 2 reasons: 1) You have moved the canvas away and the particles no longer can touch it - 2) You baked the simulated while it was moved. As a result, nothing happens when you press the playback button. Baking means the result is saved in memory or disk and used until it gets deleted. To fix the replay, select the Text (Canvas) object and press ALT+G to reset its position. On the Physics tab, go to Dyn. Paint > Cache and press the Delete Bake button. The replay will show now the live-data again. $\endgroup$
    – Blunder
    Mar 7, 2022 at 11:35
  • $\begingroup$ When it works again you can press Bake to save the simulation data. Now you can move the text around (or whatever you want, scale it, rotate it, turn off the particles) and the burn effect will still be visible. If you want to change the sim you need to delete the bake and re-bake again. For the fire & smoke simulation (Mantaflow sim) the bake is required to see the result. (I read that's a workaround because of a bug. The replay only works the very first time. Just a bit annoying). Other physics sims (like cloth) usually work live. But baking can prevent calc errors & get a better result. $\endgroup$
    – Blunder
    Mar 7, 2022 at 11:46
  • $\begingroup$ OMG, it works! This is such a rewarding feeling :-) . I have no idea why/how I moved my canvas away but I now get everything working as it should. I will go on to the rest of the tutorial and see if I can achieve the desired result. It looks like the DP was a bit of a tricky one for a beginner like myself to start with but I got it to work with your help and learnt so much along the way. This is great, so cool! Thanks so much again. dropbox.com/s/dwg7nqqznkm1bld/BurnEffect_01.JPG?dl=0 $\endgroup$
    – JG1XMV
    Mar 7, 2022 at 11:59
  • $\begingroup$ As a follow-up, this is the final result: dropbox.com/s/cx8ko55xgxrrtur/… . I have learnt a lot in the space of a few days, including on the topic of rendering as I had to solve a couple of issues along the way. One thing I noticed is that when I re-run the rendering, the first letter seems to have some blemishes that it did not have before even though I did not change anything. Weird but no bid deal since I had saved what I wanted already. Working on adding the sound was fun as well. Amazing what a beginner can do in Blender! Many thanks again. $\endgroup$
    – JG1XMV
    Mar 9, 2022 at 10:48

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