Keep twins tidy

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

DoDownload p3-11-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-twins.blend

You should seeThe 3D view looks straight down at a round plate with a large stone in the middle and six smaller stones evenly round it. The Outliner, the list at the top right of the window, holds the plate and seven stones.

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

WhereThe sidebar, the CAD/CAM tab. Click Gems in the section bar, then in the Gems panel click the title of the sub-panel Symmetry to open it, and scroll down (turn the mouse wheel, or slide two fingers on the touchpad) to the box This group.

DoClick the Round 3.00 in the middle of the plate, then press Select Group.

You should seeNothing changes, and that is right: this press is meant to be refused, and nothing is harmed. The centre stone is not copied, so it is in no group. The box This group says “The active item is not in a group”, and the status bar, the line along the very bottom of the window, says “The active item is not in a symmetry group” for a moment before it fades.

It worked whenThe box This group says “The active item is not in a group”.

WhereThe 3D view, then the box This group.

DoClick the petal at the top of the flower, then press Select Group.

You should seeAll six petals orange, the petal you clicked a lighter orange: it is the master, the stone the others copy. The centre stone is not orange. The box now reads “Master of 5 twins”. A group is the master and its twins, and the count includes the original.

It worked whenThe box This group reads “Master of 5 twins”.

WhereThe 3D view, then the box This group.

DoClick the petal at the bottom of the flower, then press Unlink.

You should seeThe petal stays selected and the box This group now says “The active item is not in a group”: it is a stone of its own. The status bar says “1 object made independent” for a moment. Unlink makes a twin independent, with its own copy of the stone’s mesh, so that it no longer follows.

It worked whenThe box This group says “The active item is not in a group”.

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

DoPress G, Y, type -0.6 and press Enter.

TypeG, Y, -0.6, Enter

You should seeThe freed petal at the bottom moves 0.6 mm down and the other five stay where they are. Before Unlink, a move of one petal moved all six.

It worked whenThe petal at the bottom stands farther out than the rest.

If it goes wrongNothing moves: The pointer is still over the sidebar. Move it over the 3D view and press the key again.

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

DoClick the petal at the top, then press G, Y, type 0.2 and press Enter.

TypeG, Y, 0.2, Enter

You should seeThe petal at the top and the four twins that are still in its group move 0.2 mm out, to 3.25 mm from the middle. The freed petal stays at 3.65 mm: it is not in the group, so a move of the master does not reach it.

It worked whenFive petals stand 3.25 mm from the middle and one stands 3.65 mm.

If it goes wrongNothing moves: The pointer is still over the sidebar. Move it over the 3D view and press the key again.

WhereThe 3D view, then the box This group: the button Delete (keeps twins tidy), the wide button at the foot of the box.

DoClick the petal at the top, then press Delete (keeps twins tidy).

You should seeThe master gone from the top and five petals left: four in the group and the freed one. The group is not lost: the add-on hands it to one of the twins, which becomes the new master, the petal at the upper left. Click it and the box reads “Master of 3 twins”. Click another petal of the group and the box reads “Twin of” and the new master’s name.

It worked whenThe petal at the top is gone and five petals stand round the centre stone.

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

DoClick the petal at the upper right, then press G, X, type 0.2 and press Enter.

TypeG, X, 0.2, Enter

You should seeThe petal moves 0.2 mm to the right and the other three petals of the group move to match, each turned the same way round the middle. The group is four petals now: the new master at the upper left and three twins. It still follows although its first master is gone.

It worked whenThe four petals of the group are the same distance from the middle.

If it goes wrongNothing moves: The pointer is still over the sidebar. Move it over the 3D view and press the key again.

WhereThe 3D view. Move the pointer over the dark area.

DoClick the petal at the upper left, which is the new master, press X, then click Delete in the small menu.

You should seeThe petal gone from the upper left, three petals of the group left and the freed petal at the bottom. Blender’s own delete removes the stone and nothing more: it does not hand the group to a twin as Delete (keeps twins tidy) does, and the Symmetry sub-panel shows no warning. The status bar says “Deleted 1 object(s)” for a moment. Delete a master with the add-on’s button instead.

It worked whenFour petals stand round the centre stone.

WhereThe Symmetry sub-panel: the button Re-sync, at the top beside Live. Scroll the sidebar up to it.

DoPress Re-sync, then click the petal at the lower left.

You should seeThe status bar says for a moment what it did: “Re-sync: 0 stray cleared, 0 groups repaired, 0 twins rebuilt, 0 removed, 0 moved”. Nothing was repaired. Scroll the sidebar down to the box This group: for the petal at the lower left it reads “Twin of CJ_Gem_Round_2.50x2.002”, the name of the petal you deleted in step 9, and “Not a regular array”. The three petals still name a master that has gone, and Re-sync does not mend that here. Delete a master with Delete (keeps twins tidy), as in step 7.

It worked whenThe box This group reads “Twin of CJ_Gem_Round_2.50x2.002”.

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-twins and carries no asterisk.