In this blog, our design team engineer Jorge will give our visitors some introduction of animation rendering by AutoCAD Inventor. The featured video you see in our crowdfunding requires extensive design of individual parts, assembled into a virtual mechanical product. The animation will be produced based the assembly file.
Before creating an animation using inventor, the first step is to finish the 3D model which will be animated. All the pieces or assemblies need to be constrained. In most cases, at least one piece should be grounded (this will not be the case when the object you are creating needs to be displaced). In this particular case, the BETE engine should have at least one piece grounded because it won't move from its starting position (Only internal pieces will move or rotate here).
After the model is completed, the next step is to constraint the pieces which will move using the "Motion constraints" feature.
There are 2 main kinds of constraints here:
- Rotation: this is used when a piece rotates thanks to the action of another rotating piece. For example a pair of spur gears.
You only need to define the ratio of rotation and the direction.
- Rotation-Translation: this one is used when the rotational movement of a piece, creates a linear movement in other, or vice versa. A common use of this is a Rack gear with a pinion spur gear.
The things that need to be defined are the direction, and how much the linear piece will advance every time the rotational piece completes one turn.
For this specific animation, the motion constraints that will be used are:
- Rotation-Translation constraints, so that when the pistons move back and forth in a linear way, the rack gears will make the pinions rotate.
This also applies to the SM Carriage where the rotation of the output spur gear, will make the carriage move.
- Rotation constraints, so that all the rotational movement from the gears, can be transferred to their respective pairs of gears. Eventually this rotational movement goes to the output shaft, and will move the Synchronous belt to create the output electrical energy.
Now that the motion and assembly constraints are created, you can move on to the animation.
To start the animation, go to the "Environments" tab, and then "Inventor Studio".
First create an animation. Procedure: In the left panel of inventor, right click in "Animations", and select "New animation".
Name the animation after it is created. Right click in the animation you just created and select "Activate". Make sure it is active by having a blue check.
This will be the file in which our animation will be created. Nevertheless, you can create multiple animations if you want to.
Next step is to create a scene style. Click in the "Scene Styles" button.
Select "New Style" in the upper left button of the window that appeared.
After it is created, right click on the new style and select "Rename Scene Style". Change its name.
Right click again and "Activate" the scene style, because this is the scene we want to use for the animation.
In this example, the Scene is called "BETE Motor Scene".
There are somethings which should be defined for the scene.
Select the type of background you want and its color. You can use a gradient background with two colors, or import an image to use as background. In this case we'll use a single blue colored background.
Select the direction of the ground plane, and an offset if necessary. Also, define the shadows and reflections percentage.
Click in the "lighting styles button"
Right click and "Rename Lighting Style". After that, right click and "Activate".
In this example, the lighting style is called "BETE Motor Lighting".
Right click in the new lighting style, and select "New Light".
There are some things which have to be defined here:
- General Tab:
The first thing to do is to select a target for the light to point to. After that you may change the position from where the light comes from. Select what kind of light you want. You can even flip the light direction.
Select the color of the light you want and its intensity (in percentage).
- Shadows tab:
Select the type, quality and density of the shadows.
- Directional tab:
Define the latitude and longitude where the light comes from.
You can click OK now and the light will be finished.
If you need additional lights you can repeat the process. In the lighting style you created, right click and select "New Light". Define all settings for the new light. You can create several Lights inside a Lighting style.
Next we have to create a camera so we can "Record" the clip from a specified angle.
First, set the inventor into a View you would like to use for the camera. Then, go to the tree in the left side of inventor and right click on the Cameras Icon. Select "Create camera from view".
In this example, I wanted the camera as my home view.
After created, change the name of the camera if you want to. Then right click and select "Edit".
In the previous picture, the rectangle shows what is going to be displayed from this camera view.
You can create additional cameras if you need to.
These are the basic settings you can set in order to improve the quality of your animations. Now we can start to create the clip timeline.
Click in the "Animation timeline" button.
A timeline for the current animation will appear.
The first thing will be to define the animation options. Click in the "Animation Options" button located in the upper right side of the animation timeline.
Here you have to set the total length of your clip. You can also change the "Default Velocity Profile" so that the animation uses a constant speed, or a non-constant speed which you can define. After setting this, click OK.
The main things we want to animate in the clip are:
First we will define the starting position for the camera. Click in the list box located in the right side of the animation timeline, and select the camera you want to use (In this case, the one we created before. It's called BETE Motor Home View Camera in this example).
Click on the camera icon called "Add Camera Action" which is in the left side of the list box. Now the clip will start with this camera view at the beginning of the animation.
Now we can take a look at the action editor. Click in the "Expand Action Editor" button, located in the right side of the animation timeline window. Here you can see in detail what is going to happen in the animation. So far, we can see that the camera view will be set in the second 0 of the animation.
Now let's suppose we want to leave the camera static for 3 seconds. The procedure to do this is: Change the time of the clip to second 3. You will see that the blue timeline will change its position to 3.
Click again in the "Add Camera Action" button (the one with a camera picture). Now you will see that the Camera view Timeline will be filled in blue from second 0 to second 3. That tells us that the view will remain static for these 3 seconds.
Let's animate the camera moving. For example, let's say I'd like to move from the actual view to another corner in 5 seconds. In the clip, this will go from second 3 to second 8.
Select second 8 of the animation.
Now go to the view of the model and rotate it to where you want to go with the camera.
Click again in the "Add Camera Action" button. The timeline will be filled in blue from 3 to 8. During these 5 seconds, the animation will go from the starting home view, to the second view we defined before.
Let's say I want to animate a piece of the assembly moving.
Click in the "Animate Constraints" button.
Now you have to select the constraint you want to animate from the left tree. These constraints were created before in the 3D CAD model. In the example, I selected "Mate 16" constraint to be animated.
Here you can select: the start and end of the constraint animation. Also you need to define the start and end time for the animation.
In the example, I'm animating Mate 16 from 105 mm to 15 mm. This will happen in a 2 seconds lapse, starting in second 8 and ending in second 10 of the clip.
Additionally, you can set the velocity profile for this animation. You can set a constant or specify a custom speed.
After clicking OK, the animation will appear in the timeline.
This is pretty much what you need to know about this topic. You can always animate several constraints, even at the same time.
Click in the "Animate Fade" button.
Select the component or components you want to fade. Select the Start and End Percentage of fading. After that, select the Start and End time for the action.
In the example, I will Fade Piece "01_003" from 100% to 0%. This will make the piece completely invisible. The action will be completed in 2 seconds, from second 10 to second 12 of the clip.
Again, you can configure the velocity profile.
After clicking ok, the animation timeline will show the fade animation.
At this point, with all the settings made so far, and the Animation Constraints created, you can start to render.
- Render Image:
You can render a single image to determine if a view angle is OK. Select the "Render Image" button.
Select the desired Width and Height of the image.
The Camera, Lighting and Scene Styles, should be the ones we created earlier. Finally, Choose a Shaded render type to increase realism.
Go to the output window. Select if you want to save the image or not.
Select the level of anti-aliasing. Increasing this value will result in greater realism but the rendering time will increase drastically.
In the last window, you can select if you want the true reflection feature. Again, this will increase both the quality of the animation and the time to render it.
Now click OK to see the result.
- Render Animation:
Click on the "Render Animation" button. Some of the settings here are the same. The "General" and "Style" windows have the same settings than when rendering an image. Those settings should be the same.
The changes are in the "Output" window.
After all is done, click in "Render".
After the rendering is completed, you will have a lot of images. Now you can use a Video editing software to complete the animation, for example, the Windows Movie Maker.
Import all the rendered images to the Movie Maker and set the time each image will be displayed. This depends on the frame rate you chose before. For example if you chose a frame rate of 20, it means you will show 20 images per second, so every image should be displayed for 0.05 seconds.
Export this file to a video format and the animation will be completed.