Building a plate from sub-parts created from merged prisms is a great way to learn the fundamentals of Blender. Let’s break down how you can approach this, starting from the initial square.

Here’s a step-by-step guide to get you started:

1. Starting with a Square (Plane):

• Add a Plane: When you open Blender, you’ll likely see a default cube. Delete it by selecting it (right-click) and pressing the ‘Delete’ key (or the ‘X’ key then the ‘Delete’ key). Now, add a plane by pressing the ‘Shift’ key and the ‘A’ key together, then selecting “Mesh” and then “Plane”. This will be your initial “square.”

2. Resizing the Plane (Your Initial Sub-part Base):

• Enter Edit Mode: Select the plane (right-click) and press the ‘Tab’ key to enter Edit Mode. In Edit Mode, you can manipulate the individual vertices, edges, and faces of your object.
• Scale the Plane: Make sure all vertices are selected (press the ‘A’ key if nothing is selected). Press the ‘S’ key to enter Scale Mode. Now, move your mouse to make the plane larger or smaller. You can also type in numerical values while scaling for precision (for example, press the ‘S’ key then type 2 to double the size). If you want to scale along specific axes, press the ‘X’ key, the ‘Y’ key, or the ‘Z’ key after pressing the ‘S’ key (though for a flat plate, you’ll mostly use the ‘S’ key directly or the ‘S’ key then the ‘Shift’ key and the ‘Z’ key together to scale in the XY plane).
• Extrude to Create Height (Prism): To turn your square into a prism, you need to give it height. In Edit Mode, select the top face of the plane (right-click on it). Then, press the ‘E’ key to extrude. Move your mouse up or down to create the height of your prism and left-click to confirm.

3. Creating Additional Prisms (For Merging):

• You can create more prisms in a few ways:
  • Duplicate and Transform: Select your first prism in Object Mode (press the ‘Tab’ key to exit Edit Mode). Press the ‘Shift’ key and the ‘D’ key together to duplicate it. Press the ‘Enter’ key to place the duplicate in the same location, then immediately press the ‘G’ key to enter Grab Mode and move the duplicate to a new position. You can then enter Edit Mode (the ‘Tab’ key) to resize and reshape this new prism as needed using the scaling (the ‘S’ key) and extrusion (the ‘E’ key) techniques described earlier.
  • Add New Primitives: In Object Mode, press the ‘Shift’ key and the ‘A’ key together, go to “Mesh,” and select “Cube.” This will add a new cube. You can then scale it down along the Z-axis (press the ‘S’ key then the ‘Z’ key) to make it flatter and then further resize it in Edit Mode to get the desired prism shape.

4. Resizing Individual Prisms:

• Object Mode Resizing (Overall Scale): Select the prism in Object Mode and use the ‘S’ key followed by the axis keys (the ‘X’ key, the ‘Y’ key, the ‘Z’ key) if you want to scale along a specific axis. For uniform scaling, just press the ‘S’ key and move your mouse.
• Edit Mode Resizing (Vertex, Edge, Face Manipulation): Enter Edit Mode (the ‘Tab’ key).
  • Vertex Selection (Press the ‘1’ key): Select individual corner points (vertices) and move them (the ‘G’ key) to change the shape.
  • Edge Selection (Press the ‘2’ key): Select lines connecting vertices (edges) and move, rotate (the ‘R’ key), or scale them (the ‘S’ key).
  • Face Selection (Press the ‘3’ key): Select flat surfaces (faces) and move, rotate, scale, or extrude them.

5. Merging Prisms:

• Object Mode Merging (Joining Objects): If you want to combine entire prisms into a single object (which might be useful for creating a single sub-part of your plate), select all the prisms you want to merge by holding the ‘Shift’ key while right-clicking on each one. Then, press the ‘Control’ key and the ‘J’ key together (or go to Object > Join). This will combine them into a single object. Be aware that their individual geometry will remain separate until you perform further operations in Edit Mode.
• Edit Mode Merging (Connecting Geometry): If you’ve joined objects or if your prisms are already part of the same object, you can merge their geometry in Edit Mode:
  • Vertex Merging: Select two or more vertices that are close together or overlapping and press the ‘Alt’ key and the ‘M’ key together (or go to Mesh > Merge) and choose an option like “By Distance.” Adjust the merge distance in the pop-up menu if needed.
  • Boolean Operations (for Overlapping Volumes): For more complex merging of overlapping volumes, you can use Boolean Modifiers.
    1. Select one of the prism objects.
    2. Go to the “Modifier Properties” tab (the blue wrench icon in the Properties panel on the right).
    3. Click “Add Modifier” and choose “Boolean.”
    4. In the Boolean modifier settings, set the “Operation” to “Union” (to combine), “Difference” (to subtract), or “Intersect” (to keep only the overlapping part).
    5. In the “Object” field, select the other prism object you want to interact with using the eyedropper tool or by typing its name.
    6. You can “Apply” the modifier to make the change permanent.

Building Your Plate from 4 Sub-Parts:

1. Plan Your Plate: Visualize or sketch how you want your plate to be divided into four sub-parts.
2. Create the Base Shapes: Start by creating four separate planes (your initial “squares”). Resize them to the approximate dimensions of your sub-parts.
3. Extrude into Prisms: Give each of these planes some thickness by extruding them.
4. Shape Each Sub-Part: Enter Edit Mode for each prism and use the scaling, moving (the ‘G’ key), and potentially further extrusion of faces to create the specific shapes you need for each sub-part of your plate. You might merge smaller prisms together within each sub-part at this stage using the techniques described above.
5. Position the Sub-Parts: In Object Mode, move (the ‘G’ key), rotate (the ‘R’ key), and scale (the ‘S’ key) the four sub-part objects to arrange them in the desired configuration for your plate. They don’t need to be perfectly touching at this stage if you intend to “glue” them virtually.
6. Optional: Joining the Sub-Parts: If you want your plate to be a single object in Blender, you can select all four sub-part objects and press the ‘Control’ key and the ‘J’ key together to join them.

Tips for Learning:

• Practice Regularly: The more you use Blender, the more comfortable you’ll become with its tools and interface.
• Follow Tutorials: There are countless excellent Blender tutorials online for beginners. They can guide you through specific techniques and projects.
• Experiment: Don’t be afraid to try different tools and see what they do. Blender is very forgiving; you can always undo (the ‘Control’ key and the ‘Z’ key together).
• Break Down Complex Tasks: Your plate project is a good example of breaking down a larger goal into smaller, manageable steps (creating individual prisms, shaping them, merging, arranging).

How can I control the exact dimensions of my prism ?

There are a few ways you can control the exact dimensions of your prism in millimeters in Blender:

1. Using the Dimensions Panel in the Sidebar:

• Select your prism in Object Mode (right-click on it).
• Press the ‘N’ key to open the Sidebar panel on the right side of the Blender window.  

   

• In the Sidebar, click on the “Item” tab.  

   

• You will see a section labeled “Dimensions” with X, Y, and Z values. These values represent the current size of your object’s bounding box along each axis, in Blender’s current units.  

   

• To set the exact dimensions in millimeters:
  • First, you need to make sure your Blender scene is set to use millimeters. Go to the “Scene Properties” tab (the icon that looks like a piece of paper with a sphere on it) in the Properties panel on the right.
  • Under the “Units” settings, change the “Length” dropdown from “Meters” to “Millimeters”.  

     

  • Now, go back to the “Item” tab (by pressing ‘N’). You can directly type the desired millimeter values into the X, Y, and Z dimension fields. For example, if you want your prism to be 50mm wide, 100mm long, and 20mm high, you would type 50 in the X field, 100 in the Y field, and 20 in the Z field.
  • Important Note: Directly changing the Dimensions values in the “Item” tab will also affect the “Scale” values of your object. If you need to maintain a scale of 1.0 for each axis (which is generally good practice, especially for modifiers and simulations), you should follow the next method.

2. Scaling to Exact Dimensions (and Applying Scale):

• Select your prism in Object Mode.
• Press the ‘S’ key to enter Scale Mode.
• Now, you need to calculate the scale factor based on the current dimension and the desired dimension. For example, if your prism is currently 1 Blender Unit (which is now 1 meter if you haven’t changed the units yet) along the X-axis and you want it to be 50mm (0.05 meters), you would need to scale it by 0.05.
• You can type this scale factor directly after pressing ‘S’ and the axis key. For example, to scale along the X-axis to 50mm (assuming your scene units are in meters), you would type S then X then 0.05 then press ‘Enter’.
• If your scene units are already in millimeters, and your prism is currently, say, 20mm along the X-axis and you want it to be 50mm, you would calculate the scale factor as 50 / 20 = 2.5. Then you would type S then X then 2.5 then press ‘Enter’.
• Repeat this for the Y and Z axes.
• Apply the Scale: Once you have scaled your prism to the desired dimensions, it’s important to apply the scale to reset the Scale values in the “Item” tab to 1.0. To do this:
  • Make sure your prism is selected in Object Mode.
  • Press Ctrl + A (or go to Object > Apply > Scale).  

     

  • This will make the current dimensions the base size of the object, and the Scale values will be reset to 1.0.

Which method should you use?

• For quickly setting a specific size, directly using the Dimensions panel is often faster. However, be mindful of the Scale values changing.
• If you need to be precise with scaling and want to maintain a clean object with a scale of 1.0, the scaling method followed by applying the scale is recommended.

Remember to always double-check your scene units in the Scene Properties to ensure you are working with millimeters.