[DIY] Jack Sparrow's Compass (Work in Progress)
Posted: Sat May 15, 2021 7:59 pm
Jack Sparrow's Compass
Recently I was browsing Thingiverse for movie props and came across Jack Sparrow's compass from Pirates of the Caribbean. In case you don't recall, this is the compass that points towards what the owner most desires, and not true north.
While I've long wanted to recreate the treasure coins from The Curse of the Black Pearl, I'm holding off until I get a resin printer someday, as those have much higher quality for finely detailed objects. My current melted plastic squeezer... er, I mean plastic filament 3D printer... would leave a lot of layer lines that would be challenging to sand out without destroying the intricate details on the pirate coins. But this compass looks like a prime candidate for 3D printing in plastic, with nice large flat sections and almost no intricate details.
While checking out the compass model on Thingiverse, and comparing it to screenshots from the film, I quickly realized that the model was not accurate. For example, here's the main compass body - notice in the details that it has deeply inset panels on a thick solid frame, the triangles in the corners extend to the edges of the octogon, and the hinge extends the full width of the edge:
But in the movie scene, the panels are fairly flush with the frame, the frame is segmented as if it was assembled from smaller segments, the triangles are smaller and don't reach the corners (and seem thinner too), and there is a noticeably smaller hinge:
I also had to consider how to actually print this model. I really hate using supports, as they mar the finish and require a lot of post processing to clean them up, and with the way this model was designed, there wasn't a good angle to minimize supports.
So I decided that if I was going to bother with this prop, I was going to have to recreate the design from scratch, so I could achieve the level of realism I wanted, while making design changes to make printing easier without excessive support structures.
NOTE: After much research, I see that the compass design is not consistent even in the Disney movies. Some have the larger triangles. The face decal (called a compass rose or windrose, or "Rose of the Winds") has two different designs. This is quite common in movies, where props change from movie to movie, or even in the same movie (Indiana Jones and the Raiders of the Lost Ark have two medallion designs in the same movie, made by two different prop houses, and used for different scenes). Of the various designs, I prefer the look of the smaller triangle design shown above, so that's my target.
Also, before starting down this path, I like to check and see if an official prop already exists for purchase. I found a lot of hand-made examples that didn't even pass the glance test (one glance and you knew it was fake), and even the good ones still looked like painted plastic. The more I thought about creating my own, the more I preferred this path, as it allowed me to integrate some alternate materials like real wood. Perhaps I could even make this the nicest replica of them all.
Beginning the Design
The first step was to get the dimensions right. I started with the screenshots showing the compass being held in-hand, and positioned my hand in a similar pose, and measured between my thumb and fingers. Obviously hand sizes differ, though with Johnny Depp being about the same height as I am (he's 5' 10", I'm a smidge less than 6'), I figured my hand was similar in size to his and would be good to measure. I determined that the compass size is likely between 80mm and 90mm, probably close to 84mm by the looks of it. Also, the creator of the Thingiverse model had graciously provided the Fusion 360 model for download, so I examined that one and found it was sized to 82mm.
Next I needed to determine the size of the fileted corners. I did this by measuring some screenshots and plugging the values into a spreadsheet to come up with a general ratio of side-length to corner-length. I found that the corners were approximately 55% as long as the sides. I then created another formula to plug in different lengths and see what came out. I put my engineer's hat on for this task - and by this I mean I went at this as if I was designing a prop from scratch with no specs, and used nice round numbers. For example, I figured it was more likely that the side was a rounded 47mm long, and not a fractional 46.8423mm.
By plugging in nice round numbers into my spreadsheet, I found that that if you divided a square into a tic-tac-toe grid, with the central section exactly 47mm wide, and the corner sections exactly 18mm wide, that you ended up with an overall size of 83mm. And the 18mm wide corners create a diagonal that is 25.5mm long, approximately 54% of the 47mm length. Obviously these numbers are still just guesses, but if you change them by even 1 mm in any one direction, you get a significantly larger/smaller model or throw off the ratio of corner length to side length, so I went forward with the dimensions I had calculated.
In the design, I placed fairly large, exaggerated gaps between the various metal frame segments and wood panels. Below you can see my design in progress on the right, with the original Thingiverse design on the left. I made the gaps between the wood panels and metal sections larger than the gaps between the metal to metal joints, as I figured that more closely resembled real-world manufacturing techniques.
I also again used nice round'ish numbers for sizing the metal frame. The circle I sized to 4mm wide, the edges to 3.5mm wide, and the corner triangles to 3mm wide. I think I was right to guess that an engineer designed this in CAD before making the model, and likely used similar if not identical numbers in their design. It's the same thing I do when designing parts, as I prefer seeing round numbers in a design versus long fractional numbers. Ditto with the circle diameter, which I sized to 70mm, a nice round number that also cut into the triangles quite similarly to the actual movie prop.
I then printed out a quick sample to see how well the gaps looked in plastic. I put a little paint on the metal frame portions to give it some pop. I like to do partial sample prints to test out design choices, you can save a lot of wasted plastic and time versus printing a full model. This sample only used $0.12 worth of plastic and about an hour to print. Had I printed the full part, it would have taken closer to 6 hours and about a dollar worth of filament.
And for easier side-by-side comparison, the movie screenshot:
I felt I was on the right path, and that the result was not bad for an hour's work. Holding the part in my hand, recreating the grasp shown in the movie, the overall size seems really good. Happy with the new design, it was time to think about the overall design plan, which would incorporate real metal and wood.
Next Steps
I'm very early in the design process, and can't get too much further until I get some materials ordered and delivered. I also need to watch some of the movies to find more compass scenes for design reference.
I find that plastic painted to look like metal still looks too much like plastic. Instead, I am thinking of using some metalized tape to cover the frame segments. I would really like to use a brass metalized tape, but I can't really find such a product. It seems I can either use aluminum/silver metal tape, or copper tape. I'm worried that the copper may look too orange - some of the film shots look more silver than brass, and definitely not coppery. So I'm leaning towards using a silver aluminum tape, and weathering it with paint to give it an antique look, possibly with brass tones.
Once I get some metalized tape, I need to apply some to my sample prints and see if the large gaps are in fact too small - I fear that the tape will be so thick that it makes the gaps fill up. I plan to adjust the gaps larger if needed to account for the tape's thickness.
Then I will finish a preliminary model design that has separate, non-printed panels for the wood sections - and here's what's really cool: I plan to have the wood panel sections laser cut in Walnut veneer by Ponoko. Since the real-wood veneers can have a significant variance in thickness from sheet to sheet, I then have to wait for the laser cut walnut panels to be delivered before making final design tweaks to the model. I will adjust the depth of the panel cutouts to match the real veneer thickness, and also adjust the wood-metal gap to get the right inset effect to match the real movie prop. I figure it's easier, quicker and cheaper to adjust my printed model to fit the actual cut veneer sections than the other way around.
I'm super excited about making this a true multi-media build, with real wood panels and metal foil hiding nearly all the plastic. Additionally, I will have a small bit of real leather cut to go inside the lid, which is a detail you can see in some movie prop versions. Once this is done, I think the only visible plastic portion of the compass case will be the dome on top.
Stay tuned for updates...
Recently I was browsing Thingiverse for movie props and came across Jack Sparrow's compass from Pirates of the Caribbean. In case you don't recall, this is the compass that points towards what the owner most desires, and not true north.
While I've long wanted to recreate the treasure coins from The Curse of the Black Pearl, I'm holding off until I get a resin printer someday, as those have much higher quality for finely detailed objects. My current melted plastic squeezer... er, I mean plastic filament 3D printer... would leave a lot of layer lines that would be challenging to sand out without destroying the intricate details on the pirate coins. But this compass looks like a prime candidate for 3D printing in plastic, with nice large flat sections and almost no intricate details.
While checking out the compass model on Thingiverse, and comparing it to screenshots from the film, I quickly realized that the model was not accurate. For example, here's the main compass body - notice in the details that it has deeply inset panels on a thick solid frame, the triangles in the corners extend to the edges of the octogon, and the hinge extends the full width of the edge:
But in the movie scene, the panels are fairly flush with the frame, the frame is segmented as if it was assembled from smaller segments, the triangles are smaller and don't reach the corners (and seem thinner too), and there is a noticeably smaller hinge:
I also had to consider how to actually print this model. I really hate using supports, as they mar the finish and require a lot of post processing to clean them up, and with the way this model was designed, there wasn't a good angle to minimize supports.
So I decided that if I was going to bother with this prop, I was going to have to recreate the design from scratch, so I could achieve the level of realism I wanted, while making design changes to make printing easier without excessive support structures.
NOTE: After much research, I see that the compass design is not consistent even in the Disney movies. Some have the larger triangles. The face decal (called a compass rose or windrose, or "Rose of the Winds") has two different designs. This is quite common in movies, where props change from movie to movie, or even in the same movie (Indiana Jones and the Raiders of the Lost Ark have two medallion designs in the same movie, made by two different prop houses, and used for different scenes). Of the various designs, I prefer the look of the smaller triangle design shown above, so that's my target.
Also, before starting down this path, I like to check and see if an official prop already exists for purchase. I found a lot of hand-made examples that didn't even pass the glance test (one glance and you knew it was fake), and even the good ones still looked like painted plastic. The more I thought about creating my own, the more I preferred this path, as it allowed me to integrate some alternate materials like real wood. Perhaps I could even make this the nicest replica of them all.
Beginning the Design
The first step was to get the dimensions right. I started with the screenshots showing the compass being held in-hand, and positioned my hand in a similar pose, and measured between my thumb and fingers. Obviously hand sizes differ, though with Johnny Depp being about the same height as I am (he's 5' 10", I'm a smidge less than 6'), I figured my hand was similar in size to his and would be good to measure. I determined that the compass size is likely between 80mm and 90mm, probably close to 84mm by the looks of it. Also, the creator of the Thingiverse model had graciously provided the Fusion 360 model for download, so I examined that one and found it was sized to 82mm.
Next I needed to determine the size of the fileted corners. I did this by measuring some screenshots and plugging the values into a spreadsheet to come up with a general ratio of side-length to corner-length. I found that the corners were approximately 55% as long as the sides. I then created another formula to plug in different lengths and see what came out. I put my engineer's hat on for this task - and by this I mean I went at this as if I was designing a prop from scratch with no specs, and used nice round numbers. For example, I figured it was more likely that the side was a rounded 47mm long, and not a fractional 46.8423mm.
By plugging in nice round numbers into my spreadsheet, I found that that if you divided a square into a tic-tac-toe grid, with the central section exactly 47mm wide, and the corner sections exactly 18mm wide, that you ended up with an overall size of 83mm. And the 18mm wide corners create a diagonal that is 25.5mm long, approximately 54% of the 47mm length. Obviously these numbers are still just guesses, but if you change them by even 1 mm in any one direction, you get a significantly larger/smaller model or throw off the ratio of corner length to side length, so I went forward with the dimensions I had calculated.
In the design, I placed fairly large, exaggerated gaps between the various metal frame segments and wood panels. Below you can see my design in progress on the right, with the original Thingiverse design on the left. I made the gaps between the wood panels and metal sections larger than the gaps between the metal to metal joints, as I figured that more closely resembled real-world manufacturing techniques.
I also again used nice round'ish numbers for sizing the metal frame. The circle I sized to 4mm wide, the edges to 3.5mm wide, and the corner triangles to 3mm wide. I think I was right to guess that an engineer designed this in CAD before making the model, and likely used similar if not identical numbers in their design. It's the same thing I do when designing parts, as I prefer seeing round numbers in a design versus long fractional numbers. Ditto with the circle diameter, which I sized to 70mm, a nice round number that also cut into the triangles quite similarly to the actual movie prop.
I then printed out a quick sample to see how well the gaps looked in plastic. I put a little paint on the metal frame portions to give it some pop. I like to do partial sample prints to test out design choices, you can save a lot of wasted plastic and time versus printing a full model. This sample only used $0.12 worth of plastic and about an hour to print. Had I printed the full part, it would have taken closer to 6 hours and about a dollar worth of filament.
And for easier side-by-side comparison, the movie screenshot:
I felt I was on the right path, and that the result was not bad for an hour's work. Holding the part in my hand, recreating the grasp shown in the movie, the overall size seems really good. Happy with the new design, it was time to think about the overall design plan, which would incorporate real metal and wood.
Next Steps
I'm very early in the design process, and can't get too much further until I get some materials ordered and delivered. I also need to watch some of the movies to find more compass scenes for design reference.
I find that plastic painted to look like metal still looks too much like plastic. Instead, I am thinking of using some metalized tape to cover the frame segments. I would really like to use a brass metalized tape, but I can't really find such a product. It seems I can either use aluminum/silver metal tape, or copper tape. I'm worried that the copper may look too orange - some of the film shots look more silver than brass, and definitely not coppery. So I'm leaning towards using a silver aluminum tape, and weathering it with paint to give it an antique look, possibly with brass tones.
Once I get some metalized tape, I need to apply some to my sample prints and see if the large gaps are in fact too small - I fear that the tape will be so thick that it makes the gaps fill up. I plan to adjust the gaps larger if needed to account for the tape's thickness.
Then I will finish a preliminary model design that has separate, non-printed panels for the wood sections - and here's what's really cool: I plan to have the wood panel sections laser cut in Walnut veneer by Ponoko. Since the real-wood veneers can have a significant variance in thickness from sheet to sheet, I then have to wait for the laser cut walnut panels to be delivered before making final design tweaks to the model. I will adjust the depth of the panel cutouts to match the real veneer thickness, and also adjust the wood-metal gap to get the right inset effect to match the real movie prop. I figure it's easier, quicker and cheaper to adjust my printed model to fit the actual cut veneer sections than the other way around.
I'm super excited about making this a true multi-media build, with real wood panels and metal foil hiding nearly all the plastic. Additionally, I will have a small bit of real leather cut to go inside the lid, which is a detail you can see in some movie prop versions. Once this is done, I think the only visible plastic portion of the compass case will be the dome on top.
Stay tuned for updates...