Re: Those damn’ chines

DELFTship forum Hull modeling Those damn’ chines Re: Those damn’ chines

#36211
Icare
Participant

Theory:
If you wish to cut plywood planks based on your design, you have to keep in mind that planks can be bent in only one direction (they aren’t rubber made!). That is you can make a cylinder (a pipe), but you can’t bent the cylinder and make a torus (a donut) or close its edges (and form a sphere) or bend a square in two opposite directions (and form saddle shape). You can experiment this for cheap, just using paper ­čśë It the paper makes a crease instead of a smooth bend, the plank will break.

In Delftship/Freeship, each plank (of wood) must be drawn on a different layer (of virtual tracing paper). Thus, if your design is correct, DS/FS will unfold each plank without stretching it.

Practice:
So, once the bottom is drawn, rename its layer “Bottom”.
Create a new layer and rename this new layer “Border”, and change its color, too (this makes easier to see which layer you’re working with).

Now, select the Border’s layer, then select the bottom plank’s outter edges, and extrude them upwards and slightly outwards. This wild create the border’s ***base*** in the Boarder’s layer (i.e. in an other layer than the bottom’s), and they will be knitted together (this will avoid the leak points).

Now, select each point on the border’s top (one after other) and move it to its final coordinates. Check for the ┬źdevelopability┬╗ of the planks using the convenient button (in FreeShip v.5.x, the red hull in the right of the Home menu). Note: The Gaussian Curvature can be used, too (the green and orange hull, besides the Developability button)… if you can understand the colors meanning. Think of setting the precision rendering as high as possible with the ┬źLow/Medium/High/Very High┬╗ button (on the left of the Home Menu).

Then, you can check for the unfolded design using the Unfold button (Tools menu).

I quickly made a five-planks model to show you the operations and the buttons (using FS 5, but these buttons exists in older versions, too). You can find bellow the different stages of the operations on the screenshots below, and I added the model’s file (for FS 5).