Re-Animating a Camera Move in Post

Hi Ian, thank you for writing back. Short answer: it was the framerate Filmed in 24 fps and blender running by default in 30 :) No wonder things were moving strange .

Ian Hubert

Did you ever get this figured out? Unfortunately there are a BUNCH of little things that could cause that (for example, if you have a video clip, and swap it out in the node editor for another one, it'll ignore the frame number and reset it to 1, and uncheck "auto refresh", so you have to redo that every time you swap em out)- so make sure it's actually using more than just the first frame. Also- I know you know, but if the 2k version is at all a different frame range, it won't sync up anymore. That said- you posted this a few days ago- were you able to figure it out??

So here is my problem: I motion tracked a 4k scene (mov file)-> Camera projected on planes with UV project modifier (emission object of course).. all good. Now I want to change the footage that is emitted to 2k format or a smaller resolution of that initial mov file because the viewport is running with 2 fps and I cannot really work with 4k footage in the viewport, but when I repoint the projection again (change basically just the file from 4k to smaller) the camera projection starts sliding on the objects instead of being fixed, like the textures move

👏👏👏👏👏👏👏 BRaVo 👏👏👏👏👏👏👏

Kai Christensen

This is actually a real technique that was used on the inside-the-black-hole bookshelf scene in Interstellar! While all the copies of the set were digital, the instance of it that Matthew McConaughey was interacting with was real geometry with moving, stretched textures being physically projected live onto the set while he was performing. CG is awesome, don't get me wrong, but practical stuff still blows my mind all the time!

Jourdan Biziou

Terrific :) Thanks Ian for the generous gift of your process. Great lessons and fun to watch !

Ian Hubert

Me neither!! I'm going to use it all the time, haha!

yes, that would be great

Mike L. Taylor

Wow! Great tip about the projection modifier. I had no idea that existed. Lol

Ian Hubert

Oh! I saved over the file seen here in the video to make the final version of the project, but I could potentially re-create it? Would uploading just the footage be useful?

hi ian, me again. Do you think you can share the 3d scene from this tutorial? I would like to try it if I can. regards

Sure, it sounds very logical, in that case, I think it all lies in doing good modeling and looking for the ideal framework to do the projection, right? Thanks for answering my questions, I feel like I'm a little less ignorant today.

Ian Hubert

Oh! No idiotic at all! With typical projection mapping, you just have to line up the model with the image (ideally lining it up with the cameras POV), and everything's great. But if you're dealing with footage, the perspective of the camera can be different on every frame as the camera moves, so you can't just use the camera's perspective on the first frame, or everything'll get funky really quick. This might not be applicable for your situation, though!

excuse the idiotic question. What do you mean by updating perspective?

Ian Hubert

Me too! Hahaha. So many things I kept avoiding (3d motion tracking and all that), and I'm so glad I've finally gotten into it!

Ian Hubert

Ah, thanks Carter!! Yeah, I figure this should be possible in most programs, it just has to be able to update the perspective it's "projecting" from- and it sounds like that's pretty standard? Even if not, projecting from a static camera onto 3d geometry could still open some pretty cool doors!! Very excited to see what you do with it!!

Carter Burr-Kirven

Definitely! You could do this in any software that supports camera projection onto 3D geometry—Fusion, Nuke... you could even do it in After Effects, although you'd be limited to planes instead of proper geo.

oh, did my previous comment die? Thanks for this, it's a diamond

OH THIS IS GREAT, I AM NEW HERE AND I AM AMAZED. COULD THIS SAME TECHNIQUE BE REPLICATED IN BLACKMAGIC FUSION?

If Blender doesn't generate a right flame/smoke for Ian, then Ian generates flame/smoke for Blender. :-)

Ian Hubert

Done!!

Thanks for this Ian! I've been looking how to do Projection Cameras in an effective way for a long time ! I wish I knew it was so easy hahah Thanks!

Ian Hubert

Oh man yeah! It's usually just footage of steam set up as the mix factor for a translucent/transparent material on a plane (usually in the viewport, sometimes in the composite). I shot some new elements a while back that I want to get all optimized/loopable, and I'll post em here with a tut soon! :D

Max

Hey Ian! You do fantastic things! and I have a question for you: Will you make a lesson about steam and smoke that you use in your shots? it would be amazing!

Thanks Faust, I tried that but didn't work for me. Anyway, in the end I rendered my animation shadows using shadow catcher + cycles and redenred the rest using holdout shader + eevee.

Ian Hubert

Totally!! This is effectively projection mapping. The process of lining up the render with an actual projector on actual geometry could be tricky, but yeah! Oooo Actually yeah- if you set up the projector as another monitor, you could actually just work in the viewport and have it project on the scene in real time- could make it a lot easier to line everything up!

Per Kofod Hansen

hmm - I wonder if some of this could be used to light the real world with CG lights using a projector (in real world)

Zeke Faust

you can use the shader to rgb node to generate an alpha mask for the shadow

Hi Ian, thanks again for your amazing work. It's not directly related with this video but can you show us how to cast shadows when using 3D and real footage and Eevee? I know how to do it using cycles but not with Eevee. Thanks!

wow. is ther an update on the greenscreen tut Ian?

Ian Hubert

Oh! yeah, I can try to upload a couple clips today :)

Mario Taylor

Amazing!! Thank you!

Ian Letarte

holy cow

akim mohideen

amazing.. waiting for the green screen one... thanks

Lethal Bacon

Amazing stuff as always! Have you got any spare footage like this that you could give?, as I would love to experiment with some quality footage similar to this. Even some spare green screen footage with a moving camera would be awesome to test.

Doug Brown

Woa... way beyond my skills... I barely understood any of that... but hey I can see you are a force for good... So good!

Nathan Vegdahl

I'm really enjoying seeing all of these workflows you're coming up with, which seem to basically be using Eevee as a 3d compositor. Super cool stuff!

shonal bose

Ian this Technic is used a lot in nuke..they have it as (project cam) where they project the camera texture and have model builder node to build the set...seeing you do this in blender is really refreshing...is it possible you send can the project file so we can see this workflow...

max pirrit

would love to see the finished shot

Ian Hubert

Wait what!?!? Okay let me do a test render. -Okay yeah, fortunately renders alright in Cycles/Eevee. I wonder what was happening on your end? Were you using the UV project modifier? I don't think it's used very frequently, so it's likely it could still have some bugs. ALSO OH HELLO! Thanks for being here :D

Left Swift

Thank you so much for sharing. Cant wait to try this!

Ian Hubert

Oh man yeah! You could totally track in other cameras! On one hand I'd say it'd make more sense to leave the camera locked down on a tripod, but on the other hand, the 3d movement helps you get the point cloud, which helps make recreating the environment waaayyyy easier (although you could also use an app like DisplayLand to get a reference model of the environment, then project the footage onto THAT- could give you great parallax data).

Mark Miller

Slick, man. Would be interesting to track in multiple cameras moves with other detail (like the patio on top). The freedom to not match the original camera move perfectly is pretty powerful. Do you know if blender can track 360 degree camera footage?

Did it still work as expected when rendered? I tried to do a similar thing recently and the texture coordinates did not update correctly when rendering the animation (it only worked in the viewport).

Erich Stenzel

Yeah. Ian. Ok. Just stop. Stop already. Speaking for myself, you are making me feel like a total clod! "Look at this toothpick I modeled," I say to my cat. She still loves me. :-D

Leo Nobu

This is gold! Omg

Chris Ras

Amazing! :)