# Drawing a star 3D lamp

A client is asking for a 3D, 7-armed star, which shall form a lamp. Total dia 72cm. Thickness around 10cm.
The lamp construction shall be a skeleton built out of thin (3mm) bars.
I am a SU user for 4-5 years but still see this as a challenge…
Greatful if anybody could give me a clue on how to draw this?
I have a picture and sketch from the client which I can mail on demand - didn`t find a way to enclose it here.

Hi,

Thickness 10cm but it also says the construction is made from 3mm bar? Am I missing something?

Best Wishes
Ian

My bad explanation. The bars in the skeleton shall be 3mm – they shall form a structure being 10cm thick at center, with the star arms thickness decreasing outwards and be very slim at ends.

A bit diffcult to explain – enclosing a picture and a sketch to better explain the project.

illustrasjon.pdf (749 KB)

It depends on how the arms are arranged. Are they all pointing outward, or are there arms point up and down? An image would help a lot. Either way, you have to do a tiny bit of math to determine the general shape (pentagon, heptagon) and then you would model an arm component that you would place and rotate/array duplicates of.

I imagine the 10cm is the thickest part of each arm, and the length is less than half the diameter of 72cm. This doesn’t seem too complicated, but a little more info can get you more help.

Okay. So your angle between the centers of each arm is 360/7. That’s good.

I would start by drawing the center column line up 10cm, and group it, and then drawing a single line out from the center to 36cm. Group that and rotate it in an array for your 7 arms. Then you can simply start playing connect the dots to build an arm component of lines. A little follow me to give each line a 3mm thickness and you’re set to put it together.

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Hi Ben

Bad explanation from my side – a bit difficult especially in foreign language.

Enclosing a picture and a sketch from the client to explain better.

All arms pointing outward, thickest in the middle and arm thickness decreasing outward.

illustrasjon.pdf (749 KB)

I think you have put me in the right direction – thanks a lot Ben!

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I’ve made one if you want it, but you should try you’ll get it I reckon

It’s a pretty simple shape to make using inferencing, but you do need to know (or decide) the inner dimension of the points.
Once created you just need one triangle to get the lengths of all your rods.

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Thanks a lot guys, I´m on the right track now.

Enclosing my preliminary model.

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Have you noticed that has 8 points and you originally mentioned 7 points.

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Ohhh… saw it now, thanks for noticing that!