Inkscape: Using Clips & Masks
Following on from yesterday’s faceted diamond shape, I’m going to show you a few ways to tidy up the edges without the need for time consuming node editing.

Here’s our shape from yesterday. In order to make it look more diamond-like we’ll need to get rid of those sharp edges and form it into a more uniform shape. 
If you look at the shape, you could fit the areas where two or more colours overlap into a 12 sided shape so make a polygon and fit it into the shape. I’ve outlined it here to show you but what you need is a white dodecahedron (I’ve been waiting to write that!) filled white at around 30% with no outline. It should fill most of the diamond shape.
The 12-sided polygon will be used to shape the diamond.
There are two ways of doing this; clips and masks.
Clip
Move your 12-sided shape on top of the diamond. For clipping it doesn’t matter what colour your top shape is as this won’t show when the clip is applied. Select the diamond shape and your 12-sided shape and go to Object>Clip>Set. Everything under your 12-sided shape will be showing and anything outside of it is hidden. You can undo it by going to Object>Clip>Release. The image below shows the diamond shape with the polygon positioned on top, then after clipping is applied.

Mask
Mask works in a similar way to clipping except that it retains some of the properties of the mask object. This time the white semi-opaque colour of the 12-sided shape will be applied as well as the clipping. This will give the coloured object the transparency of the mask above. Here’s how it looks now:

That’s possibly too transparent but you get the idea. Release the mask and adjust the transparency on the mask object and reapply the mask if you’re unhappy with it.
Note: If you want to apply a gradient as a mask use a black>white gradient.
If you copy and paste in place the mask object on top of a clipped object you can give the diamond a more glassy look:

Play around with it until you end up with something you like. All the files for this are available from yesterday’s tutorial including the various clipped and masked objects with explanations.


Start by making a six-sided polygon with equal width and height. Set the transparency to 33%. Copy and Paste another 3 polygons and colour them red, green, blue and white. Arrange the red green and blue hexagons so that they each have a side touching another colour and place the white hexagon on top spanning the red, green and blue shapes.
