Sweep and Arcs

[Anonymous]

Good morning,
i'm trying to make a solid like the one shown in the picture below in order to use it for solid operations. The final object has to be fully parametric so i cant use inserted objects (from 3ds, maya etc) or morphs.
Sweep cmd seems to be my only choice and in the "GDL Reference Guide" pg 87 is mentioned that
"Additional status codes allow you to create segments and arcs in the planar polyline using special constraints."
Although when i'm trying to use the POLY codes to insert the path this msg drives me crazy every time:
"too many parameters"
Have any of you tried to do something like that ?

[Erich]

How are you using the additional status codes? It works fine here.

    PUT 0'-0.0000", 0'-1.0000",     1, 
        0'-0.0000", 0'-0.0000",    900, 
        0'-0.0000", 590'-6.6142",   4001, 
        0'-0.0000", 0'-1.0000",     1
		profpts=NSP/3

	PUT	0'-0.0000", 0, 0'-0.0000",
		0'-0.0381", 0, 0'-0.8716",
		0'-0.1519", 0, 0'-1.7365",
		0'-0.3407", 0, 0'-2.5882",
		0'-0.6031", 0, 0'-3.4202",
		0'-0.9369", 0, 0'-4.2262",
		0'-1.3397", 0, 0'-5.0000",
		0'-1.8085", 0, 0'-5.7358",
		0'-2.3396", 0, 0'-6.4279",
		0'-2.9289", 0, 0'-7.0711",
		0'-3.5721", 0, 0'-7.6604",
		0'-4.2642", 0, 0'-8.1915",
		0'-5.0000", 0, 0'-8.6603",
		0'-5.7738", 0, 0'-9.0631",
		0'-6.5798", 0, 0'-9.3969",
		0'-7.4118", 0, 0'-9.6593",
		0'-8.2635", 0, 0'-9.8481",
		0'-9.1284", 0, 0'-9.9619",
		0'-10.0000",0, 0'-10.0000"
		pathpts=(NSP-profpts*3)/3
	
	SWEEP profpts, pathpts, 0, 1.1, 1+2+4+16+32, GET(NSP)

[Anonymous]

Thank you for your reply,
my problem is defining the path with status points in order to be able to construct the new object changing the parameters (start point, end point, angle or something like that) and not to calculate path points coordinate.

[Barry Kelly]

If you are trying to use a start point, centre point, radius, endpoint to define your path I don't believe you can do this as the sweep path are simple x,y,z co-ordinates and have no status codes for centre and arc.
You have to define each path in the sweep using SIN & COS similar to the example used in the TUBE command in the GDL reference manual.

If it is a circular path you need to follow the REVOLVE can do that but this won't work for an elliptical path.

If this is not what you are meaning the please ignore my reply.

Barry.

[Erich]

Yeah, Barry's answer is spot on. You cannot use the status codes for your path, only your polyline surface. The Sin/Cosine route is necessary for a mathematical curve. In my example I just simplified things by laying out and arc and segmenting it and getting the XY coordinates. But that doesn't work well for a parametric path.

[Anonymous]

Thank you,
you were all very helpful. My original intention was to create the path using arc polylines. Now I know that it can't be done so I'm creating a cos/sin function for path points' determination. Additionally the number of path points will have to be inserted in the UI as a precision factor. It will be a users' choice between precision and memory consuming object..
We can't have it all

[Erich]

You can use the RESOL and TOLER functions to define the complexity of the object. This may be an easier route than alternate path points. Of course it will affect not just the path but any other curved elements as well.