This weeks’ tip of the week is for the drafting users in the audience. It’s a little known shortcut for making arcs from polylines. (Note that this will not work with linestrings)
![](https://lh6.googleusercontent.com/CFc8kTudp7QBeDOJoear3fq7O8cePtTxdtVljKZvZZ_Of8NZOQ6cqGObtGralTJOLgbdqqntEcS7bdKYNpu-d-Lgl2DLsUpowHknVc7yKfhdPmY-55sDQKstntokrVGN_uinYQ4V)
Start by drawing a polyline. It can be as simple as one line or a complex feature.
![](https://lh6.googleusercontent.com/DPXoemTUTnROrKjR_vKj08kWBdgP2PfCFkbC3yTJM_BNiRZRAcILppDlN6C6KlsBgomxQDuIEgz7hPYBOI1IVwgN6gnxTvWmXZvMmK73kNY--VZI0DikG1DLR1SGwjdaOiBZM-H8)
Next, in File > Options, or from the Quick Access Toolbar.
![](https://lh4.googleusercontent.com/bQRrXbZwrboexi_whl1ajcZUyc5rOaOhCRyUQYVPQLsItSXvmp0vp3gK7pZjPv0BEg0VhMgoYWxCygSLeNrEyBvsGTEecYAsf5WAPtDozVBSjF7stkJdC-2snr0iOArDQ5n23DyF)
Ensure the “Turn on CAD grips” checkbox is selected.![](https://lh3.googleusercontent.com/eytNDs1-3mLjSqhYxu-yPa6ASiaJeyVsICWjtliICnZyDu1nsY3i2DakVui8FmdNT91qUOOCJp2OtiH0fLMxpRw-QT_UW2nBgDebrpTfWUSOKAmSL5_mY4zmA4aIalWZaYVXUOUL)
This toggles end and midpoint grips for straight lines and curves.
![](https://lh3.googleusercontent.com/U-wWWwNuCeBcwiBCC57S-jCDB8Ar1cNO2nCajb9qAQVfHXJS0t0NDCrJgx0pwS2Fu6KzNjMM9FoHoHPxTwdKubKFxczAmahIUgoCf2-Q5xuhW3kWHqO-dhnrBg5db42Oszn6Eo7-)
![](https://lh4.googleusercontent.com/7odEFJK9XJ98GG60Q3fYWI1_f6xv1wQm7br1rJBgGj46jbjU4eQpVqgbcxTVYMA8sbFMpJxljQKX8tcEg-6uNTMVBc_IwVV-wJzoqNX5tYSq_HZwls6Ag-BgXSebe4bmwuEFq-vt)
With the rightmost polyline selected, double click on the midpoint grip, represented by a triangle. (End points of polylines are represented by squares)
![](https://lh6.googleusercontent.com/-h3Df1KSKAo9nh_6GN_MK8s_bsf9af_RXd_OZO5F6Pkl_iRn-56NzMKq_48tL-I79eJEbkA_kpv0BVExkaME86voxMmVux4EhLJBpsPpEE-5MNe7MyfxTVoFXH0e4iI_dytxhD5c)
The polyline changes to an arc, wow!
By clicking and dragging the midpoint grip, the radius of the arc can be adjusted.
![](https://lh4.googleusercontent.com/nEgCPr-ntFelZOAMrUaCPr2Lbo1RLEjXmZeMhTmhFYpu2NgfvkdfuA6Pwnuf3UUFrcCAWGCOORtPtq5mRPn9YeEE19Y8y3NiyVaeq8h91wQB8fjPc0fARqqdlAc0tXRJqlrGbH_l)
Adjacent polylines can be adjusted individually, to create and replicate complex real world arc features.
![](https://lh3.googleusercontent.com/QEOSSEd1RXfZkGNef91UdW8uaKzoMQ96wFpogpNnTmUINPVfzsDwhN4l6heXN4fuqIHmuF0G0xXD9nemtPbSX8yahxaMmg0hfdNQ3HWnAoA4_0jb7CueyT5Ar--khnNgYUVb_N20)
The polyline arcs cannot be made to have a diameter larger than the distance between the two end points.
A useful application of this is the ability to draft circles with two points at opposite sides of the circle. For example, take points 100 and 101 below.
![](https://lh4.googleusercontent.com/s6FgFiiSRyDrx9Gwlha0uL-WA-iC2P__bCthyHM6zVG9Q1vD86gCXgkQTR1Bg3jQ597tcpG71d7oIr9mImroLfPgkCu1BCox5go0T6qAqoRD1FCIzRioxWSHKDZMNk0f4NG2jmD8)
Draw a polyline between the points, double click the midpoint grip to convert the polyline to an arc, and drag it the maximum distance either up or down.
![](https://lh6.googleusercontent.com/aHftNjYCfL-kPJIv4uq1tr913iKMhZDRcgy6AUa1PbLN6ZbLbQJNlY0o0JDpoTR8_IeWFwTak5XhZ3Ve5x3UFXnEsqA4P0JTOnQaMBmpwISXl0ufZPJ3ciLA3fqfSCMg7S0OXcAz)
![](https://lh4.googleusercontent.com/AMGuqjHwCUxY2phA43SpD3e3_j2yIResp-7Znky5XjSoq9TTn7MZ78nxtVnSbpKEF-2Zp2HKpnK7ONbJswWuf9Eu_UAlTXem0yMi6xhiZtYJ1RXGvSv1ZcKbJftTIiZKeBAfSS2L)
This creates a semi-circle with a diameter the distance between points 100 and 101.
Repeat the process, except this time drag the midpoint of the arc the other direction, and a circle is formed.
![](https://lh6.googleusercontent.com/J4FKdW-mEtyFo6RiJh1VI7owfBAVQlht0IPO3LPPhdqzIlduYFRtbEgCNNo7HAx6P0FT3DvW9EUHLAnUjyXRkbPv6-PJy3_DW_Eow0aOKMxIKYuChVN-Cy5NVopxbq7j5-lFUBrt)
And voila! A circle from two points. Break time? Break time.
TBC - Field to Finish with Confidence.