Hi, I'm trying to re-create a logo reveal because I want to change some things about the original. The original shows a bulldozer plowing through an ice floe/field, and the path it leaves behind is where the logo will appear.
The original is located here: https://elements.envato.com/bulldozer-logo-reveal-7UKFDV4
(I can link to an mp4 version if it will help)
I want to change the type of bulldozer (done) and make the wheels turn as it moves (also done). The other change is to replace the "ice" with a chunk of stylized ground - green on the outside faces and brown on the inside faces. I created an animatic here:
(Current settings for my active and passive rigid bodies are in a reply below.)
Here's a list of things that I have been unable to re-create from the original:
- The shards are rotated flat in the same orientation after the vehicle passes. Mine are rotated randomly.
- None of the shards in the original end up behind the vehicle in the plowed path. Some of my shards end up in the path behind the vehicle.
- It looks like there are 2 more solid planes on either side of the path that have minimally fractured edges and are located under the solid plane that the vehicle is shattering. Those edges seem to be animated in reaction to the vehicle's passing, but I can't tell if it was done manually or if it is a result of physics colliding with the vehicle or the main group of shards.
I would greatly appreciate any advice or suggestions, please. Thanks!
Passive animatic bulldozer cube settings:
Active animatic shard settings:
Update:
I think I've found a way to keep the debris out of the path behind the bulldozer: I added a passive floor beneath the fractured solid and gave it a Box type collision. I also changed the collision type for the cube from the default to Sphere. That gives a much more bulldozer-like displacement of the fragments. I turned off the visibility of the new floor in both the viewport and the render so I could keep the plowed path transparent.
I'd try disabling the Deactivation in the Settings of the shards, so they will be able to lie down again after the tractor has passed (if needed, you can even lower the Origins to the bottoms of the shards, that might help as well).
The rest, you seemed to have figured out already.
Thanks, Martin. I tried your suggestions, and they only made a tiny bit of difference. The shards didn't lie down after the tractor passed; they froze in the position and orientation they had as a result of the collision. Moving the origins didn't seem to do much, either.
I'm new to this rigid body stuff, and Blender physics in general. Might force fields be appropriate here?
(NB: I did experiment with force fields, but I couldn't get them to affect the shards at all, even at ridiculously strong settings. The only objects in the scene that I could move with force fields were the solids.)
After many tweaks and coffee breaks, here is the best version of the animatic that I've been able to make:
Hi Jeff,
That looks indeed like they are colliding with whatever you use to prevent the shards from going into the path behind the tractor.
Maybe make a Collider Object (with little to no Friction), something like this and Parent it to the Tractor (here: Cube):
Physics Simulations are a lot of fun, but they also consist of a lot of tweaking Settings and often even changing setups.
Great idea, Martin! I was just using physics to keep the path clear, but I think your setup will give me more flexibility. This brings a couple of questions to mind: What is the practical difference between using a passive rigid body in this setup versus a collider object? I've been surprised a few times by which objects can pass through which other objects during the simulation. For example, I need the tractor to be able to pass through the floor and/or ceiling planes that I use to restrict the vertical movement of the shards.
Thank you again for the idea!
Oh, I think you need to make the 'collider' an Active and Animated Rigid Body, just like the tractor. Or even make it part of the tractor, but with a Transparent Material.
All Objects that are part of the Simulation should be Rigid Bodies, I believe and you can't simply Parent the 'collider' to the tractor, as I originally proposed, that is not allowed.
I don't do a lot of Physics Simulations, so when I do, I just have to figure things out along the way.
The Vertical restriction of the shards, shouldn't need floor and ceiling planes...I mean the actual floor where the tractor rides on, should prevent the shards from falling down and Gravity should prevent them from going up too much, right?
"Oh, I think you need to make the 'collider' an Active and Animated Rigid Body, just like the tractor. Or even make it part of the tractor, but with a Transparent Material."
Good info - I will try both ways. One thing, though. I've been using the tractor as a Passive and Animated Rigid Body. Is that wrong?
"All Objects that are part of the Simulation should be Rigid Bodies, I believe and you can't simply Parent the 'collider' to the tractor, as I originally proposed, that is not allowed."
I found that out the hard way. 😀
"The Vertical restriction of the shards, shouldn't need floor and ceiling planes...I mean the actual floor where the tractor rides on, should prevent the shards from falling down and Gravity should prevent them from going up too much, right?"
Partly correct. The force of the tractor + the collected shards along the front of it sometimes kick random shards up, onto and over the tractor. And there they stay for the duration of the simulation. But the floor where the tractor rides does work as you mentioned.
"I've been using the tractor as a Passive and Animated Rigid Body. Is that wrong?"
I would have used Active and Animated for the tractor, but if it works when using Passive and Animated, why not (I haven't tried that).
"The force of the tractor + the collected shards along the front of it sometimes kick random shards up..."
Maybe it helps to increase their weight...?
Thank you for your help, Martin. I have the animatic looking the way I want, even though it's not as physically elegant as the original. All I have to do is fit my bulldozer model into the animation.
Your suggestions that I use a path collider with a transparent material, that I lower the friction on the collider and tractor, and that I increase the weight of the shards really helped me dial in the animation.
To finish this topic and clean up any loose ends, here's the animatic and my tractor setup and rigid body settings:
