Blender Intermediate: Simulations and Physics

Name: Blender Intermediate: Simulations and Physics
Author: Jay Grewall

Learn how to replicate real-world physics using Blender’s physics emitters to simulate gravity, smoke, and cloth dynamics

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Course: On-Demand

Hello and welcome to Knowledge City's course on Intermediate Blender 3D. My name is Jay and today we'll be creating realistic physics in Blender. I have here on my screen a default cube which I've created, I've not applied any transformations to it, and I want it to start falling from its current location. I'm going to go ahead and select it, and in my properties panel I'm going to come over to the tab called Physics Properties. In the second column there is a button called Rigid Body, and I'm going to go ahead and click on it. I'm going to take my playback head to the very beginning of my timeline and I'm going to start playing it by pressing the space bar on my keyboard. And without creating any keyframes, I am able to create a very realistic fall of this cube. What exactly is a rigid body? A rigid body is an object which takes on real-world characteristics based upon its properties. It can further affect and interact with the physics of other objects. Let me show you what I mean. I'm going to create a basic plane and I want this cube to fall from a higher location onto this plane. So I'm simply going to move the cube up and press the space bar to start playing, and you'll notice that the cube went straight through the plane. This is because this plane is not contributing to the rigid body characteristics of the cube. So I'm going to go ahead and select on the plane. I'm going to add rigid body to this, and now let's see what happens when I press play. They both fall. This is not the effect that I want. I want the plane to remain stationary. So I'm going to select the plane, and I'm going to change the rigid body type from active to passive. Now you'll notice when the cube hits the plane, not only does it stop, but it kind of bounces. With my playback head at the very beginning, I'm going to duplicate this cube and position and rotate them in different locations. So when they fall, they fall more randomly. In my top view, I'm going to make sure that these cubes are overlapping a little bit, and I'm going to make some higher than others. And just to make it completely random, I'm going to rotate each one of them just a little bit. Now let's see what happens when I play the animation. They fall at a very realistic speed, and when they all land, they bounce round in a very realistic manner. Let's take a look at how Blender is able to do this. I'm going to start by going over to the scene properties, and you will see the word units. When I click on units, you will see the current unit system is set to metric. Underneath the word gravity, the current speed of gravity is at negative 9.8 meters per second. If we change it from metric to imperial, you will see that the speed is now negative 32 feet per second per second. The negative indicates the downward direction, and 32 feet per second per second is a speed of gravity on Earth. There are, however, two other properties of these cubes which determine how they interact with one another when they hit the plane. If we go back to our physics properties, and we click on one of the cubes, you will see that the mass is set to 2.2 pounds. When I play it, we are viewing how multiple 2.2 pound cubes will fall and interact with one another. If I decrease the mass from 2.2 to about half a pound, you will notice the characteristics are a little bit different. The other property that is taken into account is the height of each falling cube. This means that a cube, which is closer to the plane, will fall and bounce and interact differently than a cube with the same mass at a higher location. Let's see how other objects interact in our scene. I'm going to create a very simple cylinder. I'm going to scale it vertically, and I'm going to move it up here, give it rigid body properties, and let's see what happens. If I take the same cylinder and rotate it, you will see that Blender is able to calculate its exact collision with the rest of the objects when they meet. Let's see what happens when we introduce other rigid objects to our scene. I have here a bunch of spheres that are falling onto this rectangular cube. You will notice that they are falling in a very natural and organic manner. I have overlapped these spheres so that when they collide, they will roll into random directions, and when I enter wireframe, you will see that these spheres are actually rotating. I've hollowed out this rectangular cube to create a frame, and I now want these spheres to fall into this frame and hit these sides. Let's see what happens when I press the play button. You'll notice the spheres are going right through the sides almost as if the sides don't exist. In fact, if you go to the side view, you can see that the spheres are not even touching the green portion. Why is this happening? I'm going to go ahead and select this frame, and underneath the rigid body properties is the word collisions. When I click on the word collisions, you'll see the word shape followed by a dropdown menu with the word convex hull. This hull tells Blender to treat this entire object as one cube, which is why these spheres are not falling into it. What we need to do is we need to tell Blender to recognize the entire mesh as being a rigid body. So I'm going to change the shape from convex hull to mesh. Now watch what happens to the spheres as they hit the green area. Now I want to have a larger ball start from this portion of the frame and collide into all of these spheres just as they land. So at about frame 60, the sphere is going to start traveling toward the cluster of spheres and at about frame 80, it's going to collide with all of them. I'm going to go ahead and create a very basic sphere, and I'm going to position it just above the green area. With my playback head on frame 80, I want the big sphere to collide into the rest of them. So I'm going to add a keyframe on frame 80 for the location of the big sphere. And on frame 60, I want the position to be over here. So I'm going to move the sphere over to here, insert a keyframe from the location. And this is going to be the motion of the sphere. Let's see what happens when I play the animation. You'll see that the big sphere is not interacting with the smaller spheres. This is because we need to tell Blender to recognize the animation properties of the big sphere. So with it selected, I'm going to give it the rigid body properties. And underneath Settings, I'm going to tell it to be animated. Now when I play it, let's see what happens. Let's say I want the sphere to be moving at a faster speed. I'm simply going to reduce the duration it takes to go from here to collision by moving the second keyframe from 80 to 70. Now watch what happens to the remaining spheres. All the remaining spheres get thrown around in different random directions. And this is how we can create realistic physics with Blender. In the next lesson, we'll be learning cloth simulation. Thank you very much for watching.

Intermediate Provider : Jay Grewall 5 Lessons · 39m in English

Course Description

In these lessons, you’ll use Blender’s physics engine to create default objects that dynamically simulate the characteristics of objects in the real world. We’ll start by instructing Blender to apply Earth’s natural gravitational properties to cause spheres to fall and collide with a stationary object. Then you’ll move on to cloth dynamics, rigging a default flat plane to fall onto, and then wrap around, a sphere. Using the same principles, you’ll also use a default plane to “reveal” objects placed on a table.

Next, we’ll introduce Blender’s “domain,” the area in which the physical properties of 3D objects are controlled to simulate physics. We’ll also introduce emitters—the objects from which different physics originate—and use them to simulate water pouring into 3D objects and displacing upon contact. Then we’ll demonstrate how to use a domain to produce the effect of a plume of smoke rising and dissipating, and you’ll learn how to simulate rain falling into a pond of water, complete with ripples in the water as the droplets land.

What You'll Learn

Simulate real-world physics on objects using Blender's physics engine, including applying Earth's gravity to make spheres fall and collide
Create cloth dynamics by rigging a flat plane to fall onto and wrap around a sphere, and to reveal objects on a table
Set up a Blender domain to control the physical properties of 3D objects for physics simulation
Use emitters to simulate water pouring into 3D objects and displacing on contact
Produce a smoke effect of a plume rising and dissipating using a domain
Simulate rain falling into a pond, complete with ripples as droplets land

Key Takeaways

Blender's physics engine can apply Earth's natural gravitational properties to make objects such as spheres fall and collide with a stationary object.
Cloth simulation lets a default flat plane fall onto and wrap around a sphere, or reveal objects placed on a table.
A domain is the area in which the physical properties of 3D objects are controlled to simulate physics, while emitters are the objects from which different physics originate.
Emitters can simulate water pouring into 3D objects and displacing upon contact.
Domains can produce effects such as a plume of smoke rising and dissipating, and rain falling into a pond with ripples in the water.

Frequently Asked Questions

What does this Blender intermediate course cover?

It covers using Blender's physics engine to simulate real-world physics, including gravity-driven falling and colliding spheres, cloth dynamics, fluid simulation with domains and emitters, water pouring and displacement, smoke rising and dissipating, and rain falling into a pond with ripples.

What is a domain and an emitter in Blender?

A domain is the area in which the physical properties of 3D objects are controlled to simulate physics, and emitters are the objects from which different physics originate, such as water pouring into 3D objects.

What lessons are included in this course?

The lessons are Introduction to Real-World Physics Simulation, Cloth Simulation, Fluid Simulation (Part 1), Fluid Simulation (Part 2), and Emitter.

What skills will I gain from this course?

You will gain skills in Autodesk Simulation, Computer Simulation, Fluid Simulation, Physically Based Animation, Simulations, and Visual Simulations.