Sweep a section along a rail

WhereThe top bar: the row of words that begins File, Edit.

DoDownload p2-12-start.blend from Files above and open it. Then choose File > Save As and save it under the name below, in a folder of yours. Open an exercise file and keep the start file safe (P0-07) shows how.

Typemy-bangle.blend

You should seeThe 3D view shows a large open arc and two small ovals, one at the middle of the arc and one off to the right of it. The words at the top left of the 3D view begin User Orthographic. The title bar, the strip above File and Edit, begins my-bangle.

It worked whenThe title bar, the strip above File and Edit, begins my-bangle.

WhereThe sidebar, at the right of the 3D view: the CAD/CAM tab, then Draw in the section bar. The section bar is the row of small word buttons at the top of the tab.

DoClick the CAD/CAM tab, click Draw, then scroll down to the Sweep panel: put the pointer over the sidebar and slide two fingers down on a touchpad, or turn the mouse wheel.

You should seeThe Sweep panel: three buttons, Sweep1, Pipe and Sweep2, which are grey, and a line that says “Draw a rail and a closed profile, select them, then sweep.” A profile is the section: a closed curve, one that ends where it began. A rail is the open curve it is carried along. The buttons stay grey until a curve is selected.

It worked whenThe Sweep panel shows Sweep1, and its line begins “Draw a rail”.

WhereThe Outliner, the list at the top right of the window: the rows Rail and Section. They stand in a collection, a folder of the file, named CJ Draw: if you cannot see them, click the small arrow beside CJ Draw to open it.

DoClick Rail, then hold Ctrl and click Section.

You should seeBoth rows lit, and the Sweep panel reading “2 curves selected: 1 closed, 1 open”. The arc is the one open curve and the oval is the one closed curve. Sweep1 takes the closed one as the section and the open one as the rail, whichever you clicked first. Sweep1 is no longer grey.

It worked whenThe Sweep panel reads “2 curves selected: 1 closed, 1 open”.

WhereThe Sweep panel, the Sweep1 button.

DoPress Sweep1.

You should seeA bangle along the arc: a solid in the 3D view, and under the buttons the name Sweep1 1 with a list of numbers and a Weight line. The sweep is live: the numbers under the name can still change it. The oval rides the arc by the object’s origin, its small dot, which stands at the middle of the oval, so the arc runs through the middle of the oval.

It worked whenThe panel shows the name Sweep1 1, and the 3D view shows a solid along the arc.

WhereThe Sweep panel, the field Twist end (deg). Then the Item tab: the tabs stand in a strip at the right edge of the sidebar.

DoClick the Twist end (deg) field, type 90, then press Enter. Then click the Item tab, read Dimensions:, and click the CAD/CAM tab to come back.

Type90

You should seeThe oval turns evenly along the arc, so that at the far end it has turned a quarter turn: the bangle’s far end looks different, and Dimensions: in the Item tab now reads Y 64.97 instead of Y 63.00, the 63.00 of before. Twist end is the turn of the section at the end of the rail, in degrees. The start does not turn.

It worked whenThe Twist end (deg) field reads 90.0.

WhereThe Sweep panel, the field Twist end (deg). Then the Item tab.

DoClick the Twist end (deg) field, type 0, then press Enter. Then click the Item tab, read Dimensions:, and click the CAD/CAM tab to come back.

Type0

You should seeThe bangle’s end turned back, and Dimensions: in the Item tab reads Y 63.00 again. A live number is a way to try a change and take it back. Typing the old number is the way back that always works.

It worked whenThe Twist end (deg) field reads 0.0.

WhereThe Sweep panel, the Make Real button, under the numbers.

DoPress Make Real.

You should seeA new row in the Outliner, Sweep1 1 real, now the selected one. The live sweep, Sweep1 1, is still in the list with its eye shut: it is kept, hidden, so that you can come back to it. The new one is an ordinary object: it no longer follows the drawing, so no number can change it. The small eye at the right of a row is drawn closed, a curved line, when the object is hidden.

It worked whenThe Outliner lists Sweep1 1 real, and the row of Sweep1 1 has a shut eye.

WhereThe Outliner: the rows Rail and Stray. This step makes a sweep that goes wrong, so that you know its message. Your bangle is unharmed.

DoClick Rail, hold Ctrl and click Stray, then press Sweep1.

You should seeA very large ring, with a line on the Sweep panel that begins “The profile’s middle is”. It says the object’s origin, the small dot of the section, is the point that rides the rail, so the solid sits that far from it. Stray was drawn 20 mm from the middle of its plane, where its dot stands, and the sweep carries it there. The add-on says so in words, and only when the section is more than twice its own size away.

It worked whenThe Sweep panel shows the line “The profile’s middle is”.

If it goes wrongThe panel says “Select two curves” in a red box: Only one curve was selected, or three. Press Esc, click Rail and Ctrl+click Stray again, then press Sweep1.

WhereThe 3D view: move the pointer off the sidebar and into the dark area.

DoPress Ctrl+Z once.

You should seeThe large ring gone from the 3D view. The first sweep, the real bangle and your drawings are all still there. Ctrl+Z takes back the last press, and Sweep1 is one press.

It worked whenThe Outliner no longer lists Sweep1 2.

WhereThe 3D view: move the pointer over it.

DoPress Ctrl+S.

You should seeBlender writes your copy at once, with no question, because the file already has a name. An asterisk, *, in the title bar marks changes that are not saved, and it goes now. Save your work and get it back (P0-12) says more about saving.

It worked whenThe title bar begins my-bangle and carries no asterisk.