# Modeling light bulb

### STEP 2

Now, we will create a polyline that we’ll use for screw thread. But before that we need to set our Ortho settings to snap to 45 degrees. To do that, right click the Ortho in status bar and select settings. Next a window pops up where you can set angle which Ortho uses. So, set it to 45 degrees like on the image 25

image 25

The polyline will consist out of three segments. First one under 45 degrees and 0.7cm long, second one vertical 3.1cm long, and the third one will be again under 45 degrees and 1.2cm long.

image 26

Now, using command, filet the two corners of this polyline with 1cm as radius:

image 27

Now, this line is still made out of 5 curves, and if we try to make a surface out of that kind of line, then we will also get 5 surfaces, while we want only one. Why? Well, because we’ll be modeling screw threads here, and when it comes to trimming if we trim one surface with one polysurface it is very common we will run into problems with trimming. Actually, while making this tutorial I did run to the problems in terms of invalid trim. So, to avoid that we’ll just rebuild this curve using command and specifying the control points so we don’t change the original shape of this curve too much:

image 28

Now, this curve has a fairly dense control points, but since this part is going to be “dense” with threads it is ok. I guess this is the sacrifice I’m willing to give for not having problems with trim ðŸ˜‰

Using we can clearly see the number of control points. After that we can use to hide them and be able to work with the curve again.

image 29

Now, you can revolve this curve or using command make a surface. I used :

image 30

Ok, now we are going to model electrical foot contact. We need to offset the far lower edge two times. Once from front or right viewport by 1cm down, and once from top viewport by 1cm inwards (the second time we do offset we will be offsetting the already offset circle).

image 31

You can delete the outer circle, and use the smaller one and the edge to between them:

image 32

Now, using command, patch the lower hole. Be sure to select the edge, not the circle because we need the tangency from that surface:

image 33

Now, using InterpCrv command, we will create one freeform curve. Just make sure you are drawing this curve from either front or right viewport. I really can’t tell you much, except try to recreate the curve the best you can. It doesn’t matter if it is a bit too big, or a bit too small.

image 34

the curve and move it up to do the same thing. Now, using Sweep1 sweep it around edge of the middle surface, and trim with middle surface:

image 35

If you’d like, you have a small video step by step how I did it:

video 1

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used 34 commands

### 13 Responses to “Modeling light bulb”

1. […] this tutorial, naturally, you will need a model of a bulb. So, you should first read and complete Modeling light bulb tutorial and create yourself a model. Oh, you’ve done it already? No you actually just took […]

i am having difficulties making a union between the sweeped coil for the threading and the body. do you know why that is?
i just get the message ‘boolean union failed.’

3. Ivan says:

go see image 44-move. You could try extending the two ends of the V curve, and moving it a bit more like on the image. That should fix it.
if you still have problems, please post your image and/or model in the forums under this tutorial and I will help you more.

4. Ever says:

I am having the same problem with the boolean union, it just fails. There is a step I really don’t get and is precisely in the image 44, before that you had a triangle with filleted edge and after that there’s no filleted edge

5. Ivan says:

yes, you are right. Image 44 shows filleted curve, and the move image (img45) doesn’t. If you look at the img46 you will see that one has filleted corner. It is just an error in the image.
But I understand you are having problems, maybe that wasn’t explained the best way, but basically you need to have your section filleted curve positioned perpendicular to the spiral, and with trial and error you should position the curve so when you do sweep1 command you get the surface right. Meaning, it goes through the surface bottom “cap” so you can do boolean union without problems.
I might record a video of this step, it might get a bit clearer. But the important thing is you need to do this by trial and error.

6. Dioniso says:

Great tutorial, although I couldn’t do the FilletEdge of 0.1cm like image 47. I tried everything but it didn’t workout…

About the boolean union problem, just put the section (“little triangle”) on the start of the spiral burt and a move a little bit inside, to the interior (make sure your middle point is not over the end of the line) . You will get a very tiny intersection between the bulb surface and the spiral which will enable the boolean union…

7. Ben says:

What an excellent tutorial, I am so pleased i came across your Web site,
You have chosen great models to be able to cover so many techniques, and commands
Also thank you for answering peoples problems, It really help’s in solving those issue’s we have along the way

keep looking up cheers Ben

8. Perfect tutorial !
Its my first tutorial in Rhino demo ðŸ™‚
Im a MoI 3D user so its pretty easy to follow
Auxpecker plugin is amazing, this thing should be in every 3D modelling application by default !

9. Norman says:

Hi, i wasn’t able to execute the rib command. Can you please explain more specifically? Thanks a lot!!

10. Bartjan says:

Thanks for the tutorial!! It was a great help.

– Bartjan

11. […] light bulb model was done in Moment of Inspiration 3D using a Rhinoceros 3D tutorial located here It was done in both software for comparaison purposes. Check the other tutorials on the same […]

12. pontif says:

Thanks for that very instructive tutorial.

13. Leon says:

The BooleanUnion as shown in IMG46 always fails. I’ve tried everything. It’s impossible and I don’t understand why. So frustrating …