# Parametric Twisted Lamp

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## Introduction: Parametric Twisted Lamp

This is a parametric pendant lamp shade created with Grasshopper (www.Grasshopper3d.com), which is a graphic programming environment plugin for Rhino.  This instructable will cover how to manipulate the shape and design of the lamp using the included Grasshopper definition, as well as how to laser-cut the design, fold and assemble it.  If you do not have access to Rhino and Grasshopper, you can skip to the cutting and assembly portion using the included Illustrator file with 3 lamp designs.  If you do not have access to a laser cutter, but have a lot of time and patience, you can print out the designs from the included PDF and cut them out by hand.

All files are free to share, distribute, and learn from under the Creative Commons License.

This instructable was created at TechShop San Jose (www.TechShop.ws)

## Step 1: Form Development

At the beginning of the Grasshopper definition, there is a group of attributes which manipulate the overall shape and size of the lamp.

The first curve manipulates the length and scale, in an exponential function. The second curve manipulates the shape of the swell, in a sine function.

The number sliders then divide that form into helical strips, and subdivide those strips into planar surfaces.

"Sides" changes the number of strips, "U div" changes the number of subdivisions or facets, and "Offset Holes" changes the size of the triangular holes in the facets.

## Step 2: Interlocking Tabs

The design uses interlocking tabs to connect the strips.  There will be no glue or fasteners necessary.

"Tab Depth" extends the tabs outward from the lamp, "Tab Width" changes the shape of the tab from rectangular to trapezoidal, and "Tab Angle" changes the width of the base of the tab.

## Step 3: Baking and Unrolling

Once you are happy with the shape of your lamp and tabs, find the lonely "Join" function towards the end of the Grasshopper definition, right click on it and click "bake".  When the bake dialog box comes up, remember to check the box the says "yes please" next to "group".  This will bake one helical strip into Rhino.

Select your baked strip and click the join button (ctrl+J) to make sure all your surfaces are joined, then select Surface>Unroll Developable Surface from the Rhino dropdown menu.  Select your strip, and make sure Explode=No, the hit enter.

You now have a flattened strip ready to prepare for cutting.

## Step 4: Optimizing for Laser Cutting

Next find the "Brep" function next to the join function that baked your strip, right click on it, click "Set on Brep", and select your flattened strip.

You can go ahead and hide your baked strip (the lightbulb button) to make it easier to see your lines.  You will now have solid cut lines and dashed fold lines.

Now back at the main functions at the beginning of the definition, the "Dashes" slider will change the number of dashes on your fold lines.

Once you are happy with your dashes, find the last "Group" function at the end of the definition and bake it.

There you have it.  One strip ready to cut!

## Step 5: Laser Cutting

I cut my lamps on an Epilog 45w laser cutter using a card stock found at an art supply store.  Any thin rigid material should work.

If you end up using the same material I did on the same kind of laser cutter, you can use my notes on the power settings to get yourself to a good starting point.

Remember to cut the same amount of strips as the "Sides" setting used in the Grasshopper definition.

## Step 6: Folding

Begin by folding the top facet outwards, then the next inwards, and so on in an accordion fashion.  As you continue to fold, the strip will start to form the helix of your shape.

Now you can begin to fold your tabs outwards so they face the outside when it is asembled.

## Step 7: Assembly

Now that you are tired of folding, you can start attaching your strips.  Each strip will interlock side-by-side by pushing the single tab between the two smaller tabs.

The last strip can be difficult to attach, but it is worth the effort.

## Step 8: Finished!

Now you should have a fully assembled twisted pendant lamp.  I left out any parts about attaching a light fixture, since there are so many different kinds out there.  I suggest looking at what IKEA has to offer.

Be sure to take a look at the Illustrator file with 3 designs ready to cut.

Enjoy!

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## Questions

I don't know much about grasshopper, but shouldn't I be drawing some curves or points or something in rhino first in order to utilize the definition? If so, what do I draw, and what components to I associate them with? Thanks!

Sorry about that. I just updated to the latest version and found the problem. There is no need to reference any geometry in rhino. Find the 4 list items in the second group and make sure the list numbers are set to 0, 1, 2, 3, in order. It should work after that.

Hope you enjoy it! Cheers!

i made something similar few months ago. Am inspirited to make an instructable of that. http://arfurqan.com/2014/08/09/lampu/

this is just amazing. thx for sharing.

it is very gooood

Thank you! I don't have a \$5000 laser cutter, but it was a great project for my Silhouette Portrait! Unfortunately I folded it inside-out at first (yes, there is an inside and an outside), so most of the tabs are inside. Very fun!

That's awesome! Thank's so much for posting a picture! Yes, sorry, there is an inside and outside, but it looks great with the tabs inside. You can always disassemble it and fold all the tabs to the inside.

This is great unfortunately I am technologically challenged and have none of the equipment anyway. I would love to buy one. Beautiful.

5 replies

Quoting the caption from the first photo, " If you do not have access to a laser cutter, but have a lot of time and patience, you can print out the designs from the included PDF and cut them out by hand."

Aaron, thank you for creating an excellent project using high tech and not leaving out the people without access to it. Cutting out a project such as this used to be done by hand for the pure pleasure and challenge of doing it. Same with wood working. With the availability of laser cutters and CNC mills this aspect of craftsmanship is being lost. However it is being replaced by the wonderful, mental, software skills that people like you possess.

Sorry I missed the advice. I didn't read it because I was daunted by the complexity. Usually I look at the pictures first to see the basics and only read it thoroughly If I want to attempt it. I agree I can do it by hand. Thank You.

Your welcome! There are also paper/card stock/vinyl cutting machines available here: http://www.silhouetteamerica.com/select-a-silhouette. They hook up to a computer and with an inexpensive software add on can read Adobe Illustrator files. A project as big as this one would probably need to be cut in sections and joined.

Thanks for the kind words John. I'm glad you appreciate it. I hope to create more instructables that utilize computational design for the purpose of sharing and teaching, and hopefully making something useful. I think instructables is a great platform for this and digital fabrication is a great means of making things accessible to the community.

Yes, it can definitely be done by hand. I was limited to an inkjet printer and xacto blade for a long time myself.

To build this one at full size, it will either have to be printed on separate sheets and attached by adding tabs, or you can have it printed directly on cardstock on a large format printer at your local print shop. The AI file and PDF are set up on 12x24 inch sheets to fit most laser cutter beds, so you can have it printed on 18x24, or if they are capable, print 3 on a 24x36 inch sheet.

Glad you like it and hope you get a chance to make one!

P.S. I am in the process of putting together an online store, and will have links as soon as it is ready!

very nice!!!

Thank you!

Wow, I am super impressed! Looks fantastic!