Blender For 3D Printing Simple Parts

I decided to throw together a quick tutorial on the basic Blender skills that I use to design miniature conversion parts for 3D printing. This tutorial covers some simple operations that I rely on the most; perhaps later I'll go into some slightly more complex operations for more complex shapes - but only slightly more complex; I'm really just a beginner when it comes to 3D modelling!

I threw this together on a whim with no planning or anything, so it's pretty rough, but I hope reasonably clear and detailed, at least enough to follow anyway. To help I've added red borders to some screenshots to highlight buttons and icons described in the text.


Step1:
Open Blender. I'm using Blender 2.76; I believe the UI was heavily overhauled in 2.8 so this tutorial may not apply to new versions; as silly as it is to write a tutorial that's already outdated, this is the version that I'm familiar with and I believe it's still available for download so... yeah.

Step 2:

There should be a popup window with some options. Press "escape" to dismiss this window.

Step 3:

By default the 3D viewer will probably be rendering in perspective mode (so objects are foreshortened etc). I recommend Orthographic mode for modelling. At the bottom left of the screen, select "View->View Persp/Ortho" to make the switch.

Step 4:
The scroll wheel on your mouse will zoom in and out. Hold "alt" and left mouse to rotate the view. Hold "alt" and "shift" together to move the view around with left mouse (if you start rotating with "alt" and left mouse THEN hold "shift" it will instead snap the view to the axis). Try moving your view around the 3D viewport now.

Step 5:
Blender uses left-click to reposition the 3D cursor, and right-click to select objects. This takes some getting used to, but you'll pick it up soon enough. Try clicking around the 3d viewport and on the default objects to get a feel for how you interact with Blender. This is actually one of the places where new users can get annoyed and just quit Blender if they're not following a tutorial, because this part is not intuitive (I think Blender 2.8 changes it though).

Step 6:

With your mouse pointer over the 3D viewer winder, press "a" to clear the selection, then "a" again to select everything. Now press "Del" to open a deletion dialogue under the mouse pointer. If you move the mouse point out of the window it will close, so just click the left mouse button without moving your mouse (or press "enter").

Step 7:
Pressing the spacebar with the mouse pointer over the 3D viewer window will allow you to select almost any basic operation by simply typing and selecting an option. For now we'll center the 3D cursor: press spacebar, then type "snap" and select "Snap Cursor to Center". Remember this as you'll probably be doing it a lot to start.

Step 8:

Select the "Create" tab on the very left of the screen and select the shape you want to create. We'll start with a cube. Blender will create a cube centered on the 3D cursor and display editable parameters in the bottom left window. By default the "radius" will be set to "1"; this means that the sides are 2 units across. Typically 1 unit will print at 1mm, though printing services might have different standards; regardless, assume 1 unit is 1mm and scale at the end if needed.

Step 9:

To move the object, press "g" (for "grab"). The object will now move with your mouse; right mouse cancels and left mouse confirms the movement. Click on "x", "y", or "z" to lock movement to one axis. While in grab mode, enter a number to move a specific number of units. Try moving the box 1 unit along the X axis.

Step 10:

Similarly "r" enters rotation mode and "s" enters scaling mode. I will scale by 2 and then rotate around Z by 45 degrees.

Step 11:

Right now we are in "Object" mode (visible in the dropdown box just under the 3D view window). To edit individual points, we can switch to the "Edit" mode, either using the combo box or by just pressing "tab".

Step 12:

Right now all the vertices are selected. Edit mode uses the same basic controls as Object mode, so I will use "a" to clear the selection.

Step 13:

I will select one vertex using right mouse. I will then use "g" to translate it freely.

Step 14:
I didn't like that, Luckily I can undo with ctrl+z...

Step 15:

Instead I will use the "loop cut" tool: I pressed spacebar then typed "loop", and selected "loop cut". I used the mouse pointer to select the area for the cut, then used the scroll wheel to increase the number of cuts. Again, right mouse cancels the operation and left mouse confirms it.

Step 16:

Let's scale the center out. The vertices are already selected, so I just pressed "s" to scale, then "x" to lock it to the X axis, then 1.4, then "enter".

Step 17:

I then repeated this with "y" instead of "x".

Step 18:

Let's get a better look. If you hover the mouse over the small icons just under the 3D viewer window, you will find one that says "Limit selection to visible". Click this to toggle between "x-ray" mode and regular view (I may do this through the tutorial depending on what I think is clearler at any given moment).

Step 19:

Let's switch to "face" mode. Select the icon just to the left of the one we use used (marked "Face select"). You will see that vertices are less visible now, instead there are small black squares in the centers of polygon faces. Click "a" to clear the selection, the select the top face.

Step 20:

Press "e" and then move the mouse to extrude the face inwards or outwards. Left mouse confirms the extrusion and movement, however right mouse still confirms the extrusion, but not the movement. Let's use right mouse for the moment: you will see four small black squares along the edges of the face, indicating the new hidden faces.

Step 21:

Now we'll press "g", "z", "-0.5", and "enter" to move the face inwards.

Step 22:

Let's extrude it again": use "e" then right mouse again, then "s" and "0.8" to create a smaller square.

Step 23:

I will extrude again and draw upwards.

Step 24:
Now I will return to vertex mode using the small "Vertex select" icon to the left of the "Face select" icon we used before.

Step 25:

Now I use the spacebar and type "merge" (BTW you will see the "Merge" option in the menu, but next to it is "Alt M": this means that holding "alt" and pressing "m" is a shortcut to this tool). When I click on the Merge option, it will open a small popup with three options. Again, moving the mouse out of the popup closes it. Select "At Center" to merge the four vertices into a single point.

Step 26:

Let's freehand a bit. Press "k" to use the Knife tool. Holding "ctrl" will snap to vertices and halfway points on edges, which I find useful. I held down "ctrl" and left clicked on the vertex on the upper left of the face, then on the middle of the lower edge, then on the vertex on the upper right, then I hit "enter". This chained cuts to create the new edges and vertices. Hitting "escape" or right mouse at any time cancels the whole operation.

Step 27:

I want to extrude the new triangle, but I want to be careful because the vertex at the top of the spike we created previously is still selected. So I will hold "shift" and right click on that vertex to unselect it.

Step 28:

I will extrude the face by 0.5mm along it's normal, but pressing "e" and then "0.5" and "enter".

Step 29:

Right now all three selected vertices are orange. I will hold "shift" and then right click on the bottom selected vertex to unselect it, then again to select it again. It will now be white instead of orange, indicating that it is the last selected vertex.

Step 30:

I will use the "merge" tool again, but this time I select "At Last"; this merges the other two vertices into the bottom one.

Step 31:

Right now the object's "zero" (it's "origin") is at it's center. I want to change it; I select another vertex using right click (I make sure NOT to hold shift so the previous selection i cleared when selecting this new point). I then press spacebar and type "snap", and select "Snap Cursor to Selected".

Step 32:

Now I press "tab" to return to Object mode, press spacebar and type "set origin". Selecting "Set Origin" opens a dialogue; choose  "Origin to 3D cursor". You will see that the 3D cursor and the object manipulator are both centered around the point we previously selected.

Step 33:

Return to Edit mode with "tab" and select all the vertices by pressing "a" twice. Use the spacebar menu to snap the 3D cursor to the center. Now open the "tools" tab on the left, and click on "Spin".

Step 34:
OK, that wasn't very useful. There's two main problems here: first of all we are spinning around the 3D cursor, which is not currently at the object origin. To fix this we go to Object mode again and use the spacebar menu to access the "Snap Cursor to Selected" option, snapping the cursor the object origin.

Step 35:

Next we go back to edit mode and center the view from the top. We can do this by snapping to the axis while nativating the viewport as I described earlier, or we can select "View->Top" from the "View" menu at the bottom left.

Step 36:

Now we'll hit "Spin" again. This time it's a little better, but still not quite there yet.

Step 37:

When we used the "Spin" tool, the bottom-left window was populated with the relevant options (I have temporarily expanded it in the screenshots). The "Axis" option is initialised based on the 3D view window, but it can be set manually here if that's easier. Anyway, first of all we want to change "Steps" to "4", then "Angle" to "360". Voila! Now we have a cluster of spikes!

Step 38:

OK, that wasn't the best demonstration of the "spin" tool. I'll just throw together a slightly better one. I went back to Object mode, renamed the Cube as SpikeCluster, and hid it by click on the "eye" icon in the navigator in the top right. I then snapped the 3D cursor back to the center, created a new cube (and renamed it "TableLeg"), entered Edit mode and used Merge->At Cursor to get a single vertex.

Step 39:

I snapped the viewport to the Y axis ("View->Front"). I moved the vertex, then used "e" to extrude a new vertex, which I positioned freehand. I repeated the operation several times to get a fancy shape.

Step 40:

I snapped the viewport to the Z axis again, pressed "a" twice to select all, made sure the 3D cursor was snapped to the center, then used the Spin tool again with 64 steps at 360 degrees.

Step 41:
I then selected all vertices and used the "Remove Doubles" option in the Tools tab to merge the first and last vertices.

Step 42:

To make it prettier I then returned to Object mode, selected the Modifiers tab (with the spanner icon) in the bottom right window, clicked on "Add Modifier" and chose "Subdivision Surface". I set the "View" subdivisions to "2". Pressing the "Apply" button would then apply the modifier to the original geometery, which is not actually necessary (when we export the file it will happen automatically; meanwhile it can make it harder to edit the shape). This is an easy way to model a shape in an easier way (less vertices to deal with etc) then smooth it out at the end. It's also worth noting that changing the order of modifiers (using the up and down arrows at the top right of the modifier box) can change the quality of the results, especially with a Subdivision Surface, so experiment with the ordering if something looks strange.

Step 43:
Let's hide the TableLeg and make something more useful. Snap cursor to center and then use Create->UV Sphere. In the options I will set "Size" (which is the radius) to 13, for a sphere that is about an inch across.

Step 44:

In Edit Mode, I will disable the "Limit Selection To Visible" toggle (i.e. x-ray mode). Then I will press "a" to clear the selection. Finally I will snap the camera to the Y axis.

Step 45:

Now I will press "b" to enable "box select", and select the bottom two-thirds (ish) of the sphere. I will press "delete" and then choose "Vertices" from the popup dialogue.

Step 46:

I then select the bottom ring by holding "alt" and clicking on one of the bottom edges (between the vertices; clicking too close to the vertex will not selected the desired boundry); when done on an edge that is "open" Blender will try to select all the edges around that opening.

Step 47:

I now press "f" to fill the hole.

Step 48:

I go back to Object mode and create a new sphere. I set the size of this one to "2", name it "negativeSphere" and the position it freehand to be partially overlapping the dome (which I have renamed too).

Step 49:
I press "h" to hide the negativeSphere (which is the same as clicking on the "eye" icon as before). Now I select the dome again, go to the Modifiers (spanner) tab in the bottom right window, click on "Add Modifier", and select "Boolean".

Step 50:

I set "Operation" to Difference", and in the Object field I select the negativeSphere. This creates a "coutout" of the smaller sphere. Again we don't need to actually "apply" the operation yet; leaving it the way it is now allows us to come back later and move the smaller sphere around or scale it up or whatever.

Step 51:
With the dome selected, I now use spacebar and type "duplicate". This makes a copy of the Dome. With the copy selected in the navigator window in the top right, I will delete the Add Modifier operation with the X in the top right corner, to save on processing power. Now I use "g", "z", "1" to raise the new dome by 1mm.

Step 52:

I create a cube, and use the grab and scale tools to position it off to the side. The length along the Z axis doesn't matter, it just has to protrude from the top of the second dome. I have named the cube "PanelOutline", and renamed the second dome "Panel".

Step 53:

Hide the PanelOutline, then select the Panel (you can do this by left clicking it in the navigator window). Now add a Boolean modifier. Set the Operation to "Intersect" and the Object to PanelOutline.

Step 54:

I didn't like the way that the panel was rising straight up rather than out at an angle, so I un-hid the rectangle by clicking on the eye icon again, skewed it (rotating would have been fine too), then hid it again.

Step 55:

Making sure the 3D cursor was centered, I selected Cylinder from the Create tab. I then scaled and positioned it to have it protruding from the top of the dome.

Step 56:

In Edit mode, with the "Face Select" icon active, I selected the top face and clicked on "delete", then selected "Faces" to delete the face but leave the surrounding vertices. I then clicked on the "Vertex select" icon and selected the top ring of vertices ("alt" and left click on an edge, or use "b" and box-select).

Step 57:

I then pressed "e" followed by "escape" to extrude but not move the new vertices. Then "s" and "0.8" to shrink the new ring. I pressed "e" to extrude again, then immediately "z" to lock movement to the Z axis, and moved the mouse to pull the new ring downwards slightly, then left clicked to confirm.

Step 58:

Finally I pressed "e" again, then "escape", then used Merge->At Center (I could have just used "f" to fill, but I prefer doing it this way because it can be easier to edit later).

Step 59:
Back in Object mode I renamed the cylinder as "TopRing" and adjusted the position slightly.

Step 60:

I then created a new sphere, named it "stud", set the size to 1, and moved it to where I wanted it.

Step 61:

I pressed spacebar and typed "apply" to use the "Apply Object Transform" tool (which "bakes in" any rotations and translations etc, setting the object origin back to the center). In the Modifiers (spanner) tab I added a Mirror modifier and selected only the Y axis. If I needed more than two studs I probably would have duplicated the stud and rotated the new one on the Z axis around the center, then repeated this for each stud.

Step 62:
So now we have something worth printing (well, maybe...). We're going to want to export it to a more generic file format. Stl is common for 3D printing, although Obj is also very portable. Make sure everything that's part of the piece is selected; in this case we just need to use "a" to select everything. Now just use "File->Export->Stl" (or whichever format you prefer).

Step 63:
Import in your slicer of choice, add supports, generate the correct instruction file for your 3D printer, print, paint, display.