How to design from a photo

WillAdams · November 3, 2019, 11:37am

Fielded a request on the unofficial Facebook group for a sled design:

http://store.workshopsupply.com/catalogue/bild-christmaswinter-sledsleigh-pattern-p-1822.html

Since the full size thing isn’t easily doable on our machines (and I don’t want to be responsible for a child’s safety), we’ll do a model sized to a Barbie doll/GI Joe “action figure” child figure — this way it can fit on any machine, folks can scale up at need) — we’ll omit the decorative elements so as to avoid copyright issues.

First thing is researching the dimensions (not sure where my daughter’s Barbie dolls got to, and I don’t think she had any Skipper or smaller ones).

There are a number of sites which collect doll dimensions — for compleatness’ sake, here are the links found in researching this:

Unfortunately the site/page: http://www.smallhousemodels.com/wp-content/uploads/2015/09/ShM_ChairScales.jpg is offline but even as a low-resolution thumbnail this image is quite useful:

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WillAdams · November 3, 2019, 6:30pm

I was expecting the link of the plans above to pull in at least a thumbnail.

In the absence of that, hopefully posting this image qualifies as fair use:

Looking at it we can see the following parts:

back
2 sides (with attached braces)
deck (set onto 3 horizontal braces which are inset into the runners, with an additional cross brace at the back)
2 runners
steering bar at the front

Since this is 1:6 scale, we will make it 8" long which will correspond to the typical 44" dimension seen at:

rounded up to 4’

WillAdams · November 3, 2019, 7:23pm

Estimating, it looks to be about 3.5 times longer than it is high, and 4 times longer than it is wide, so we start with a stock size of 8" wide, by 8" tall so as to have a bit of working room and begin by drawing in some geometry to roughly approximate a runner:

We then finish drawing in parts/elements and begin to reduce things to the desired elements using Boolean operations:

and then assemble parts using Boolean Union:

Zoom in and use the polyline tool to fill in any defect:

and use Boolean Union to put things together:

repeat on the other side:

duplicate and drag the duplicates into position:

WillAdams · November 3, 2019, 7:33pm

Drag elements into the correct positions.

Use the curve tool to draw an approximation of the outline of the part:

Then zoom in and go to edit mode and adjust as needed:

WillAdams · November 3, 2019, 7:46pm

Draw in additional parts as needed:

and delete the guide parts:

WillAdams · November 3, 2019, 8:10pm

Draw in a rectangle and a circle to define the deck:

and union them.

Draw in 4 rectangles to define the boards of the deck:

and then inset things and use Boolean intersection to define the appearance of the boards:

You will need to select each in turn rather than doing them all at once.

and the shape will need to be inset and offset:

WillAdams · November 3, 2019, 8:30pm

Select an inset part and do a Boolean intersection:

Repeat (it will be necessary to redo the inset for the deck)

Make rectangles to define the base of the side and the side and other geometry as needed to define the desired shape, including rotation to get the back corner:

WillAdams · November 3, 2019, 8:39pm

Rotate and do a Boolean operation to define the back edge:

Then duplicate and rotate the part to determine the dimensions of the back and draw in a rectangle from the bottom edge to the top (it will be twice the desired size):

then reduce the size by 50%:

and make a note of the rotation amount.

WillAdams · November 3, 2019, 9:04pm

Use the curve tool to draw the outline for the side:

Delete the unnecessary parts and draw in the handhold and Boolean union it:

WillAdams · November 3, 2019, 9:52pm

Change the width of the rectangle to match the anticipated width of the back (equal to the deck width) and draw in circles to define the arch at the top and the handhold cutout:

Draw in geometry to shorten things and add the curve at the end:

until one arrives at the end:

Thus:

WillAdams · November 3, 2019, 10:01pm

Finish adjusting geometry:

and it should just be a matter of assigning toolpaths:

(and sourcing a dowel to serve as the handle at the front, and assembling — use butt joints for the back/sides, and if need be, drill a tiny hole to pin the cross members)

Attached.

sled.c2d (516.3 KB)

luc.onthego · November 4, 2019, 1:42pm

Bravo, Will you are an artist! Maybe I missed it but what material did you expect to use for the appropriate thickness?

WillAdams · November 4, 2019, 10:26pm

1/8" thick Baltic Birch plywood would be my choice.

Good quality thin stock hardwood if you were making a display piece — I have some Lacewood I might use for this.