This article discusses how to create a basic animation from Blender (We used version 3.0) to create the movement of the robot arm as shown in Figure 1. The content of this article introduces Animation Tab, model preparation, and put on the skeleton and Key Frame animation as a basic guide for those interested in creating further animations.
Let’s first get acquainted with the Animation tab. The look of the screen of the tab is as shown in Figure 2. This screen has 3 main functions: the camera result screen as shown in Figure 3, the timeline screen as in Figure 4, and the adjustment screen as shown in Figure 5.
From Figure 4, you can see that it is the screen for viewing the timeline of the created animation. The timeline numbers start from 1 to 250. The number of frames can be changed by double-clicking the number 250 in the lower right and changing the number to the number of frames you want. It also has buttons to play animation, pause, and move frames like a normal movie player.
If you want to adjust the display resolution or adjust the frame rate of the animation can be done from the Scene tool as in Figure 6.
Recording as a video file
Saving the rendered output as a video file can be done from the Scene tool in the Output section as shown in Figure 7. The File Format is set to Avi Raw for uncompressed AVI files and the important thing is the name and address of the file must be specified.
The characteristics of the mechanical arm to be built have the following properties (as shown in Figure 1).
- There are 3 points of rotation: shoulder, elbow and information.
- The end is the hand.
- The bottom (shoulder) is attached to the base.
- have upper and lower forearm
Build a robotic arm model
Start by adjusting the Cube to be the base to width, length and flattening as shown in figure 8, on the left, then add a UV sphere to join the header file as shown in Figure 8 on the right.
From the shoulder, add a Cube and adjust the size and make it taller for the upper arm as shown in Figure 9.
Add part of the elbow with UV Sphere as shown in Figure 10.
Do the same for the forearm by adding a Cube for the forearm and adding a UV Sphere for the data as shown in Figure 11.
Finally, add a Cube as a hand as shown in Figure 12.
Put on the skeleton
Add Armature to the scene, which will appear the name Armature in the Scene Collection as shown in Figure 13 and click to turn on the front bone display (In Front) over all objects to make it easier to see by setting it in the Properties section of the Viewport Display as shown in Figure 14.
And in the screen of the first skeleton will be found as in Figure 15, adjust the size and position it as in Figure 15.
The next step is to add the ulna bone instead of the bottom. By clicking to select Armature and changing the mode to Edit Mode as shown in Figure 16.
From Figure 17, press E to Extrude to add the bone. Move the mouse until the next bone meets the wrist, as shown in Figure 17.
Extrude again to make bone for the hand part as shown in Figure 19.
When viewed in the Scene Collection, it is shown in Figure 20: The hand bone is the child of the lower arm bone and the lower arm is a child of the forearm bone. When we move the upper arm, the lower arm and hand will move as well. And likewise, moving the upper arm will cause the hand to move accordingly. Additionally, the bone names have been changed to BoneBase, BoneArm and BoneHand.
Connecting the bones to the model
The process of welding the bone to the model made is as follows.
- Select every object as shown in Figure 21.
- Select the last bone as shown in Figure 22.
- Press Ctrl+P and select Automatic Weights welding method as shown in Figure 23.
After linking the bones to the model is complete. The next step is to check the relationship of the bones to each model by adjusting the model’s Weight Paint, the process of making it consisted of the following steps.
- Select an object.
- Change the mode to Weight Paint.
- Choose a bone piece and paint appropriately
- Red means there is a strong relationship.
- blue means no relationship
Selecting the object to check the relationship. The example in Figure 24 is the selection of the shoulder. After that, select Weight Paint mode.
The correlation is determined by selecting the draw as shown in Figure 24 and Weight being 0 will be painted in blue and 1.0 for painted in red.
Selecting the bone you want to examine or color the relationship with is done by clicking on the tool as shown in Figure 26 and a list of skeletons will be displayed according to the preset list. Click on the object name and check the color of the bone’s relationship to the model.
The relationship between the shoulders and the BoneBase is red, and for the BoneArm and BoneHand is blue, as shown in Figures 27, 28 and 29, respectively. This means that when the BoneBase is moved, the shoulders will move accordingly (Color value affects the proportion of follow-up shift).
The pose can be done by changing the mode of the bone to Pose Mode by selecting the Armature and changing the mode as shown in Figure 30.
Bone movements can be rotated, repositioned, or resized (allow the reader to play around and see the picture).
Adding Key Frame
When the object’s posture is done, press I on the customization screen (Figure 4). After that, there will be a menu item to choose from as shown in Figure 31. Before selecting, make sure that the frame number is selected in the Timeline section. The process of adding a Key Frame consists of 2 steps:
- Select a frame (Figure 31).
- Make a pose and press I to remember the value (Figure 32).
The next step is to Add keyframes and gestures after that remember the value until it meets the desired example in Figure 33, then render the animation into a video file as mentioned earlier.
At this point, we hope that readers will have a guide to creating animations with Blender that can add skeletons to created objects. And can do Key frame animation. Finally, have fun and try.
(C) 2020-2022, By Jarut Busarathid and Danai Jedsadathitikul