I downloaded Google´s free 3D SketchUp8, and it seems to be fantastic, but would take months of learning to use. My needs are for a simple to use, free 2D program that I can use to make line segments and arcs of curves. I spent several hours trying to find one. Any suggestions?

The ideal program would use an XY coordinate system and to draw a line segment; I would just imput the (x,y) of the start and finish points. For arc I would also just give the two end points, and some simple indication of the radius of curvature OR better still would be a third point on the arc the circle passes thru. Normally it would be a point on the perpendicular line bisecting the line between those two points as that would let me easily specify the diameter of the arc´s circle also.

I.e. I happen to know that (C/2)^2 = (D-x)x where C is the length of the cord between the arc´s two end points and x is the displacement of that "third point" from the cord, and D is the diameter of the circle of the cord.

Think even the old MS Paint program might serve my needs, but could not find a free download of it. I would rather have a program with more mathematical inputs like I mentioned above for arcs & line segments. (Give xy coordinates, not try to drag a pointer, as my design will need to be mathematically exact so the various parts will fit perfectly together.)

Google´s SketchUp does, on quick inspection, seem to use coordinate inputs, so if no one can help me find what I want, I plan to suggest they offer a 2D only simple version of sketchUp for people like me who only want to make simple 2D designs in a coordinate grid, not skyscrapers you can virtually walk thru.

BTW, if you are young, needing money, I bet you could earn some if you did become good with SketchUp8. I think it allows you to make a 3D building in detail and then insert it into Google Earth, as if it really existed there. I.e. your paying customer could virtually look out of the 7th floor window of the virtual building you made for him to see if the near by real building blocked his view of the sea, etc. In a decade or so, we will have trouble knowing what is real and what is virtual in the "real world." Too bad virtual food will not feed the hungry.

The ideal program would use an XY coordinate system and to draw a line segment; I would just imput the (x,y) of the start and finish points. For arc I would also just give the two end points, and some simple indication of the radius of curvature OR better still would be a third point on the arc the circle passes thru. Normally it would be a point on the perpendicular line bisecting the line between those two points as that would let me easily specify the diameter of the arc´s circle also.

I.e. I happen to know that (C/2)^2 = (D-x)x where C is the length of the cord between the arc´s two end points and x is the displacement of that "third point" from the cord, and D is the diameter of the circle of the cord.

Think even the old MS Paint program might serve my needs, but could not find a free download of it. I would rather have a program with more mathematical inputs like I mentioned above for arcs & line segments. (Give xy coordinates, not try to drag a pointer, as my design will need to be mathematically exact so the various parts will fit perfectly together.)

Google´s SketchUp does, on quick inspection, seem to use coordinate inputs, so if no one can help me find what I want, I plan to suggest they offer a 2D only simple version of sketchUp for people like me who only want to make simple 2D designs in a coordinate grid, not skyscrapers you can virtually walk thru.

BTW, if you are young, needing money, I bet you could earn some if you did become good with SketchUp8. I think it allows you to make a 3D building in detail and then insert it into Google Earth, as if it really existed there. I.e. your paying customer could virtually look out of the 7th floor window of the virtual building you made for him to see if the near by real building blocked his view of the sea, etc. In a decade or so, we will have trouble knowing what is real and what is virtual in the "real world." Too bad virtual food will not feed the hungry.

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