Bill,
Welcome to the group!
A spiral does indeed have a radius that constantly increases. Since Deltacad is incapable of drawing this type of curve using the drawing tools that are available you might still be able to draw a spiral that will be acceptable in drawing only, but not according to true architecture. Below is a picture of a spiral that is drawn by connecting an "arc with three points" to the intersections of circular and diagonal lines. Additional arcs are included to create a continuous spiral (the drawing shows alternating colored arcs to show the beginning and ending of each arc). Notice also that each arc 'point' must be connected to the next adjacent line and intersecting outer circle. Hope this helps...
Welcome to the group!
A spiral does indeed have a radius that constantly increases. Since Deltacad is incapable of drawing this type of curve using the drawing tools that are available you might still be able to draw a spiral that will be acceptable in drawing only, but not according to true architecture. Below is a picture of a spiral that is drawn by connecting an "arc with three points" to the intersections of circular and diagonal lines. Additional arcs are included to create a continuous spiral (the drawing shows alternating colored arcs to show the beginning and ending of each arc). Notice also that each arc 'point' must be connected to the next adjacent line and intersecting outer circle. Hope this helps...