topic Re: Can't use circle for tube? in GDL

Can't use circle for tube?

LeeJaeYoung — Sun, 09 Apr 2023 04:07:18 GMT

What command should I use?
I want the circle to follow a path. What should I do?

Re: Can't use circle for tube?

Bruce — Sun, 09 Apr 2023 08:24:17 GMT

Yes, you can use a circle to run along a path. TUBE is the correct command to use for this.

E.g.

TUBE 2, NSP/4, 1+2,

! Define the profile (a circle)
0, 0, 901,
frameDia/2, 360, 4001,

! Define the path (in this case defined earlier with PUT)
GET(NSP)

Re: Can't use circle for tube?

LeeJaeYoung — Sun, 09 Apr 2023 16:42:36 GMT

i would like to do this

But the reality is like this. ^^

TUBE 2,8,1+2+16+32,
0,0,901,
0.1,360,4001,

-1, 0,0,0,
0,0,0, 1,
3.230,0,0,1,
3.757,0.150,0,1001,
4.330,0.505,0,1,
4.8757,0.656,0,1001,
8.888,0.656,0,1,
8.888+1,0.656,0,0

What's wrong?
I just want to put smooth curves.

Re: Can't use circle for tube?

julienK — Sun, 09 Apr 2023 18:13:54 GMT

center point doesn't allow additional status code. It has to be 900.

Last parameter on each line is not status code like other functions. Its the angle of the profile relative to the path.

It should be 0 everywhere

TUBE 2,8,1+2+16+32,
0,0,900,
0.1,360,4001,

-1, 0,0,0,
0,0,0, 0,
3.230,0,0,0,
3.757,0.150,0,0,
4.330,0.505,0,0,
4.8757,0.656,0,0,
8.888,0.656,0,0,
8.888+1,0.656,0,0

Re: Can't use circle for tube?

Bruce — Mon, 10 Apr 2023 00:30:44 GMT

A TUBE command isn't like a PRISM command. You must define every coordinate along the path. When you do curves, the maximum angle you can 'bend' and still keep a smooth transition is 15° - any sharper than that and you will get lines at the bends.

The below code will model a rectangular hoop with rounded corners.

! Lead-in PUT -A, 0, 0, 0, 0, 0, 0, 0, A/2-cornerRadius, 0, 0, 0 cornerCentreX = A/2-cornerRadius cornerCentreY = B-cornerRadius ! Corner 1 FOR j = 0 TO 90 STEP stepA PUT cornerCentreX+SIN(j)*cornerRadius, cornerRadius-COS(j)*cornerRadius, 0, 0 NEXT j PUT A/2, B-cornerRadius, 0, 0 ! Corner 2 FOR j = 0 TO 90 STEP stepA PUT cornerCentreX+COS(j)*cornerRadius, cornerCentreY+SIN(j)*cornerRadius, 0, 0 NEXT j ! Corner 3 cornerCentreX = -A/2+cornerRadius FOR j = 0 TO 90 STEP stepA PUT cornerCentreX-SIN(j)*cornerRadius, cornerCentreY+COS(j)*cornerRadius, 0, 0 NEXT j ! Corner 4 FOR j = 0 TO 90 STEP stepA PUT cornerCentreX-COS(j)*cornerRadius, cornerRadius-SIN(j)*cornerRadius, 0, 0 NEXT j ! Lead-out PUT 0, 0, 0, 0, A, 0, 0, 0 ! Hoop TUBE 2, NSP/4, 1+2, 0, 0, 901, frameDia/2, 360, 4001, GET(NSP)

Re: Can't use circle for tube?

LeeJaeYoung — Mon, 10 Apr 2023 02:17:11 GMT

Isn't this a straight path?
Can't you make a smooth pass like a 3D modeler?

Re: Can't use circle for tube?

LeeJaeYoung — Mon, 10 Apr 2023 09:40:37 GMT

1. Below you said you can't use 1 for the radius, but you used it. I'm a beginner so it's hard to understand the difference.
Can I ask for a little clarification?

2. May I ask you to explain stepA?

(What is the value of stepA?)

Re: Can't use circle for tube?

Bruce — Mon, 10 Apr 2023 02:58:44 GMT

1. I didn't say you can't use 1 for the radius - that was julienK. You can't use status codes to create curves like you can with a prism command in the path definition. You can use status codes to create curves in the profile definition.

2. stepA is a variable I set up to be 15 (i.e. a step of 15 degrees). If you want a smoother pass through rounded corners, just make this number smaller: but I have found 15 to give a good enough result. The FOR - TO - NEXT flow control statement can also have a STEP component to it, so instead of counting up by 1, it will count by whatever STEP has been defined. Check out the GDL reference guide for more info.

Re: Can't use circle for tube?

Bruce — Mon, 10 Apr 2023 02:59:35 GMT

Yes, this is a straight path from point to point. You can't make a 'smooth' pass like you can in Rhino (for example).

Re: Can't use circle for tube?

Jochen Suehlo — Mon, 10 Apr 2023 11:45:24 GMT

Example tube ring.