In this tutorial we’re going to draw a nice, detailed, flat, single color light bulb icon. I am going with the traditional light bulb look over one of the newer styles.
This tutorial was written and tested using Inkscape 0.91 on OS X 10.10 Yosemite. While all of this stuff is probably doable with earlier versions of Inkscape, I highly recommend the latest version. Which operating system you happen to be using is less important. Inkscape has pretty much the same interface whether you’re on Linux, OS X, or Windows. I will point out any differences as they arise.
Document Properties and Snapping
Fire up the document properties window with control + shift + D. Set all units to pixels and set the document size to 500px by 700px.
Get snapping properly setup:
Begin With a Perfect Circle
Draw a perfect circle, expanding from the center of the canvas. Bring up the ellipse tool with F5, then hold down shift + control while dragging out from the center.
Convert the ellipse object to a path with shift + control + C. Alternatively, you can use the menu to do this.
Delete the segment between the bottom and rightmost nodes.
Now delete the bottom and rightmost nodes.
We should be left with a quarter of a circle, which makes up the top of our bulb.
Finish drawing the left side of the bulb. Select the quarter circle, then select the path drawing tool. The two end nodes on the quarter circle should be visible now. Click the bottom end node and complete the shape.
Select the path editing tool and clean the shape up so that it looks something like this.
Toggle rulers on with control + R (rulers may already be on by default). Click drag a vertical guide from the left ruler.
Snap the closest point of the bulb to the vertical ruler. In my case it’s the topmost node.
Using the path editing tool, click the bottom right node and drag it horizontally. Hold down control while dragging the node to keep it from moving up or down. Drag the node until it snaps to the same vertical guide that our topmost node snapped to. Lining these nodes up like this makes it easier for us to duplicate the left side of the bulb to generate the right side of the bulb.
Once those nodes are all lined up, delete the guide. Double click the guide and click delete in the dialog that pops up.
Now duplicate the left side of the bulb. With the bulb selected, hit control + D. Now press H to flip the duplicate horizontally. Drag the flipped duplicate to the right until it snaps to the left side of the bulb (now the center of the bulb). It is important to click and drag near the point you want to snap (near the top or bottom node that will end up being in the middle). A constrained drag (control drag) might make this a little easier.
With the centers properly aligned, join (union) the two sides of the of the bulb into one path. In the top menu panel click Path, Union.
Draw three sections for the base. I used a rectangle (F4) for the first section and the path drawing tool (shift + F6) for the last two sections. Use snapping to line everything up.
I ended up making the bulb portion a little taller:
Make threads for the screw base using rectangles. Draw the first rectangle so that it snaps to the bottom of the bulb but is a little wider than the rectangle we used to outline the base. shift drag the resize handle to maintain symmetry.
It was easier for me to do this with snapping off. Use shift + % to toggle snapping off. Use the same key combination to toggle snapping back on.
Convert this new rectangle to a path and bring the bottom left handle down a little (about 4px) to create an angle.
Now for the last three threads. Draw another rectangle below the first. Should be the same width. Round the edges with the rectangle tool. Rotate about three degrees counter clockwise (click the rectangle again after it’s selected to bring up the rotation handles). Duplicate twice and arrange. Just to make things easy, I made the first of the bottom three threads just how I wanted, then I duplicated with control + D and moved it down 20px with shift + down arrow, then duplicated again and moved it down 20px again. Done. If 20px doesn’t work, experiment with combinations of down arrow or up arrow with or without shift.
Delete the top rectangle that we first used to outline the base:
Change the fill of the bottom base segment so that it matches the outline color: