Simon Trümpler: Sketch #22 - Barrel Explosion



Here are my first 4 (very rough) Niagara sketches. My findings so far:

  • Takes longer than expected to do even just a sketch
  • It’s a bit frightening seeing the other threads where the sketches look like finished art works :smiley: I spent too much - but not crazy time - on my sketches and yeah, they are rough but that’s what a sketch is supposed to be I guess :smiley: It’s a very interesting challenge to put out that many very unfinished art pieces.
  • Grayscale is awesome but for some reason I always add color and then must remind myself “dude, it must be grayscale!” :smiley:


Hey there @simonschreibt! Glad to see you’re participating too!

Loved the internal explosion. Are those ribbons that you’re using to create the smoke?

By the way, I think it would be great to see those sketches without that harsh shadow in the background. Setting the walls not to cast shadows should do the trick.


Waiting for your final entries! :new_moon_with_face:

I love the internal explosion, I feel like you could exaggerate it, make it quite cartoony. Pretty fun stuff :slight_smile:

@Lush Thanks for the feedback! Yes, that’s ribbons :slight_smile: I removed the shadow now.
@Bruno Thank you :slight_smile: I like it too but I planned to exercise rendering flip books for this challenge so I “must” go with a different one.

In general I will not make it. Neither finishing the final nor finishing the missing 3 sketches. Anyway, here is a new update. I’m following the video from @AndreasGlad which is an amazing tutorial :slight_smile:


Don’t worry about not finishing the sketch!

It’s all about learning and improving your skills. Quality over quantity.


I’m continuing working on my barrel explosion. As the challenge is over I think it’s ok to add some color now :smiley:

A rough pass without any nice details like smoke trails and pre-explosion. I’ll work on that.


Love the texture and shape for the explosion texture! Houdini render i assume? how did you set up the source for the Pyro if you don’t mind me asking?

Anyway, already looking super-nice!

Thanks :slight_smile:

I’m following the tutorial from @Partikel in case you need more details but the basis is a relatively simple smoke sim out of the houdini shelve with some tweaks from Andreas (e.g. to add some noise to break up the shape), mask it so that it does not cut the texture space and make it loop-able. Really cool stuff! And yesm it’s Houdini <3


I really need to dig in to Partikel’s stuff more, everything i’ve seen so far has been a goldmine of knowledge.

Loved it, Only feedback on the internal explosion one to expand and contract the barrel.

I’m not sure if I understand…you mean, that the Barrel could contract a bit for 1 frame before it explodes?

Sorry Simon my bad, What i meant was like in Cartoons where you see the Barrels wood Expand outwards for a few frames then returns back to normal after the internal explosions, I searched for some reference but couldn’t find any. Hope that makes more sense.

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I still work on this and did the whole houdini volumes course. In case you want to see the results:

Besides that I wanted 1-2 frames before the explosion where the barrel gets distorted as a tiny anticipation. I experimented by using 1 particle with a distortion texture (the particle is moved in front of the barrel via Camera Offset to avoid having it stick in the barrel):
Why I didn’t use a normal map of a half sphere? Because in the center of the texture there’s almost no distortion happening when using a normal map taken from a half sphere. But exactly there I want a lot of distortion happen. That’s why I use this cone shape.


I’m controling the strength via particle color (my setup is messy, can be optimized):

I had fun using differente curves to get different wobbly effects:



I’m trying to get an interesting timing right now by just using basic shapes (circles). I want to bring in all elements i need (smoke, fire, debris, trails, sparkles, …) and define size and timing before starting working in the final assets/textures:


Added a little pre-flash to add a bit more punch to the whole thing:


I had this idea about a shield “protecting” the environment against the explosion (inspired by those simulations within a sphere). I was afraid that this could take away too much attention from the explosion but i think it could work. What do you guys think?


Better quality:


Added smoke trails to the debris and a cracked ground:


This is so cool to see, since I was JUST attempting the same thing with an exploding, ahem, container myself recently! Similar idea: I wanted the building to bulge outward a bit as the explosive force inside pushed against it. My solution (and not very well executed) was to use WPO on the material to push it out a bit. Now the texture can be set up better to do this right, but it’s so quick I mostly achieved the result I wanted. Additionally I wanted to see the heat from inside show through the cracks of the building so I applied a bit of that in the material as well, all animated in Blueprint with Material Parameter Collection variables.

I really like your solution though, as I think it would work great for more stylized, cartoony explosions.


Update: I tweaked it to be a bit more violent, as the first iteration was a bit sluggish for the force of the methane blast :slight_smile:

nice! to emphasize the force i would let it bulge INWARD for 1-2 frames just before it gets bulged outward. you can maybe imagine that the fire inside first burns all air and therefore it creates underpressure and then more and more stuff ignites and the actual explosion happens. i did this with my barrel in my first gifs and i think this 1 “inward”-frame adds a nice contrast to the following “outward”-force.

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