How do you add a frame to an animation in Blender?

To add a frame to an animation in Blender, you primarily insert keyframes. Keyframes mark specific points in time where properties of an object (like location, rotation, scale, etc.) are defined. Blender then interpolates between these keyframes to create the animation.

Here's how you add keyframes, effectively adding frames to your animation:

1. Select the Object: Make sure the object you want to animate is selected in the 3D Viewport.

2. Go to the Desired Frame: In the Timeline editor (usually at the bottom of the Blender interface), move the current frame marker to the frame where you want to define a pose or property value. You can drag the marker or enter the frame number directly.

3. Manipulate the Object: Transform the object by moving (G), rotating (R), or scaling (S) it to the desired position, rotation, or size for that particular frame. You can also change other properties in the Properties editor (e.g., material settings, object visibility).

4. Insert a Keyframe: There are several ways to insert a keyframe:

   • Using the "I" Key: This is the most common method. Press the I key while your mouse cursor is in the 3D Viewport. A menu will pop up, allowing you to choose which properties to keyframe (e.g., "Location", "Rotation", "Scale", "LocRotScale", "All Transforms", etc.). Choose the option that corresponds to the properties you changed.
   • Using the Object Menu: Go to Object -> Animation -> Insert Keyframe. This will also bring up the same keyframe insertion menu as pressing the I key.
   • Using Auto Keying (Optional): Enable the "Auto Keying" button in the Timeline. When enabled, any change you make to an object's properties will automatically create a keyframe at the current frame. Be cautious with Auto Keying, as it can lead to unintended keyframes if you're not careful.
   • Right-Click and Insert Keyframe: In many property panels (e.g., in the Properties editor), you can right-click on a property value and select "Insert Keyframe" to create a keyframe for that specific property.

5. Repeat for Other Frames: Repeat steps 2-4 for other frames in the timeline where you want to define key poses or property values. Blender will automatically interpolate the object's properties between these keyframes, creating the animation.

Example:

Let's say you want to move a cube from left to right across the screen over 24 frames (1 second at 24 fps).

1. Select the cube.
2. Go to frame 1.
3. Move the cube to the left side of the screen.
4. Press I and choose "Location" to insert a location keyframe.
5. Go to frame 24.
6. Move the cube to the right side of the screen.
7. Press I and choose "Location" again.

Now, if you play the animation (Alt+A or Spacebar), you'll see the cube move smoothly from left to right. You've effectively added frames to the animation by defining the object's position at key moments.

In summary, adding a frame to a Blender animation involves inserting keyframes at specific points in time to define the object's properties. Blender then fills in the frames between the keyframes through interpolation.