Create Realistic Heat Distortions in Blender! (CGC Weekly #25)

Heat distortions are a fantastic atmospheric effect that can really help sell the realism of any shot containing excessive heat. From lava to jet engines, this method will help you replicate realistic heat distortions in no time!

Spitfire Mk IXe model and textures courtesy of martinsifrar on Sketchfab.

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[ippotsk]

Whenever I see these specific node tutorial videos, it just blows my mind imagining how people even discover the node combinations that lead to these results. Hats off to you, haha.

[Kram]

A couple things:
- Because of how IOR is calculated in Cycles, your plane doesn't have the same IOR on both sides. The back side (which ever one the normal is facing away from) actually gets values smaller than 1. To fix this, you have to use the backfacing property and, conditional on that, invert the IOR with a math node (1/IOR). That's then the "thin film" version of the same effect.
- On a similar note, it might actually be a good idea to also apply a subtle normal map to the plane, because irl, we're dealing with what's effectively smoke-like (similar poofy / cloudy structure) and you aren't always looking on that straight onto the "surface" of that cloud from all angles
- "in a perfect world", you'd use a volume with varying IOR for this. In exchange the IOR variation would be far subtler than for this thin film approximation. But I don't think Cycles can do that yet.
- Maybe that idea could be approximated by using a particle system and billboards? Might just look like a mess though. Would come down to trying it out.

[stuarteliason]

At 7:00 when you’re using the Vector Math to center the gradient, you can use a Vector > Mapping node to do the same thing. You can also simply use the Object output from the Texture Coordinate node; that will be centered on the object’s origin so the gradient will be centered.
Great tutorial, I’ve been looking for an effect like this for a while! Keep up the good work!

[antonmuzik]

Mate, you're a genius. I've been trying to achieve this effect for ages. Thumbs up.

[davidfrazier]

"...Anyway...it's cool stuff, trust me!" LOL.Grant you always mange to make me smile! Great job

[syphlr]

Ty for amazing tuto & effect =) 10:56 might as well add a noise modifier to Y location to get a more random effect (unless irl heat constant) 12:30 add a damped track to camera constraint to get the heat always face the cam.

[fabioroncal]

The heat distortion planes still casting shadows

[SpencerMagnusson]

Another way I've seen this done (a longer but perhaps more accurate way) is to do a render of smoke (openGL maybe?) in the applicable area, where the smoke is white with a low density. And then you add that in the composite and plug it into the displace node. It's definitely not as quick, but the use of smoke may make it a little more accurate, and it'd hold up to multiple layers in compositing.

[codered]

Impressive result. i had the nutty idea to use this Heat distortion material in a fluid sim on my channel and it turned out great. keep up the great content!

[BiDrd]

Bizarre... While this video was loading up, a WIX (create your own website) ad came up with an almost identical table/desk and laptop as the room you recorded this video in. When I skipped the ad, it literally looked like some dude from the WIX commercial transformed into you to talk about blender. lol It was funny. Made my day.

Make your own website - by Creating Realistic Heat Distortions in Blender!

[Capkuckokos]

Actually air has the index of refraction 1.0003, it is not exactly 1. 1 is only for vacuum. Hot air has a slightly smaller IOR than air in normal conditions because it is less dense, so it is closer to vacuum. Usually in blender we approximate air with IOR exactly equal to 1, actually there is no air in empty spaces in blender, it is a vacuum. If we doing so, maybe it will be more accurate to use IOR less then 1 for hot air.

[yahlimendler]

Could you please make a tutorial on iridescence?

[DimosasQuest]

Still does the trick in blender 4.0 in 2024!

[robestey]

THAT is just too friggin COOL. Well done - thank you

[KevinSmith-qiyn]

Shiny metals can have an Index of Refraction less than 1, but they are solid materials and this affects how the light colors the metal.

[arandomlizard]

You are totally wrong. This is actually one of the few cases that you do want an IOR less than 1. You only get an IOR less than one when you go from more dense to less dense, which, guess what, is exactly what is happening.

[TheJobCompany]

Noice! At least now, during the winter freezing weather I can remind myself how much I miss summer times.

[polipano]

Hello, great tutorial. Thank you. I am trying to use this for the heat of the engines of an airplane during takeoff. However, even though the refraction plane color is pure white (1, 1, 1) and even though the Roughness is 0.00 and the IOR=1, the refraction plane is not transparent but is seen very clearly. I am working with the recent 2.8 version. Can you please assist me solving this issue? Thank you, Nissan

[Ramper]

You can actually use these to create Son Gouku Aura, then add some rotoscoping on the character to make the edges glow. You can also add some multifractal to add some color to your distortion.. Hollywood VFX...

[simoncodrington]

Thanks for the video mate. Looks great :)