Pierced Winds Grill
Continuing in the samples installment series, here is a project file and instructions for producing a pierced carving like the one on our Results page. Here we'll explore how regions, merging, and clipping can be combined to produce a pierced effect.
This project uses a technique of setting the board thickness to 0.5", then creating a rectangular region carved to a depth of 0.6". This has the effect of milling out most of the board, leaving a big rectangular hole:
New patterns placed within this hole will appear to add material back, due to the way that the default merge works -- highest depth wins:
By arranging additional carvings in such a way as to ensure a sound structural organization, a nice pierced grill can be produced:
Note how the feathering of the carving perimeters and the overlap with the outer rectangle can cause unsightly carving of the outer frame. The overlap is necessary to ensure that the carvings are firmly rooted in the frame, but we don't want the patterns to actually carve into the frame. What we want is for the patterns to only carve inside the hole portion, and not anywhere outside it. This is what Clipping does -- trim a carving to either the carved (inclusive) or uncarved (exclusive) portion of the carvings around it.
First we set all the Feather settings of the inner carvings to zero. Then we select them all and make them Clip->Inclusive from the Carving menu. The result looks like this:
The actual project file below goes one step further. It groups all the inner carvings together (well, the ones that touch the outer frame) into a single carving group, then sets the group itself to be clipped inclusive rather than all the individual carvings. This is equivalent but more organized.
Grouping is a useful way to apply merge or clipping characteristics to a group of carvings, as well as to enforce order of operations with more complicated constructions of patterns. This is a bit beyond the scope of this project, but rest assured I'll write more about this in future articles.
To see the grouping organization, select Carving List from the View menu. The list is displayed in a tree-like format, showing the relationships between the carvings and the groups.
One other minor detail that I hesitate to mention for fear of it getting a bit too complicated is that the project actually clips the carvings to a slightly narrower rectangle, allowing the outer rectangle to have a 1/4" feathered taper. I considered taking this out before posting this project, but decided to leave it in so you can play with it.
The DANGER of pierced projects is that the machine currently does not safeguard against commanding too deep a cut (but we're working on a fix). You do not need to jig this project in any way, nor apply any kind of sacrificial understructure, but you do need to take care not to command a cut more than 1/8" or so deeper than the thickness of the board you intend to use. If you do, the bit might hit metal parts of the machine and break.
As always, questions and comments are welcome. Enjoy!
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