Precision and drafting aids

A CAD drawing is only useful if its sizes are exact. Musa CAD gives you several ways to put a point exactly where it belongs. You can mix them freely, even within one command.

Type the coordinates

Whenever a command asks for a point, you can type it instead of clicking:

You type	The point is
40,25	at X 40, Y 25, measured from the drawing’s origin.
@100,0	100 to the right of the last point and 0 up. The @ means “from the last point”.
@50<30	50 away from the last point, in the direction 30 degrees. Angles go anticlockwise from the right.
50<30	50 from the origin, at 30 degrees.
50	50 along the direction the cursor points from the last point. This is called direct distance entry.
@	the last point itself.
#40,25	at X 40, Y 25 from the origin, even where Dynamic Input would read it as relative.

Lengths can also be typed as fractions or in feet and inches, such as 12 3/8 or 1'-6". A foot counts as twelve drawing units.

After a typed point, Musa CAD repeats the point it understood on the next line, for example = 100, 60 (relative @100, 0). If you typed something it cannot read, it says why and asks again.

With Dynamic Input on, you type lengths and angles into boxes next to the cursor instead. Press Tab to move between them.

Object snaps

Object snaps lock the cursor onto exact places on objects you already drew, such as the end of a line or the centre of a circle. When the cursor comes near one, a marker appears. Click, and the point is exactly there.

Running snaps work all the time while object snap is on. Press F3 to turn them on or off, and type OS to choose which ones run. To begin with, Endpoint, Center, Intersection and Extension are on.

To use a snap for one point only, type its keyword when a command asks for a point, then click. You can also hold Shift and right-click to choose a snap from a menu.

Keyword	Snaps to
END	the nearest end of a line, arc or segment
MID	the middle of a line, arc or segment
CEN	the centre of a circle, arc or ellipse
GCEN	the centre of a closed polyline
NOD	a point object
QUA	a quadrant of a circle or arc: its top, bottom, left or right
INT	where two objects cross
APP	where two objects would cross if they were extended
EXT	along the extension of a line or arc, past its end
INS	the insertion point of a block or text
PER	the point that makes a right angle with an object
TAN	the point where a line would touch a circle or arc
PAR	a direction parallel to a line
NEA	the nearest point on an object
NONE	no snap for this point, even if running snaps are on

Points from other points

These words also work at any point prompt:

• FROM: pick a base point, then type an offset from it, such as @20,10. Useful when the point you need is a set distance from a corner.
• M2P: pick two points; the point is exactly halfway between them.
• TK: tracking. Pick a series of points; each one moves along X or Y from the last. Press Enter to use the last one.
• TT: pick a temporary point to track from, then move along a tracking line from it.

Ortho, polar tracking and object snap tracking

Aid	Key	What it does
Ortho	F8	Keeps the cursor to horizontal and vertical moves from the last point.
Polar tracking	F10	Shows a tracking line when the cursor is near one of the polar angles, every 90 degrees to begin with. Change the increment from the status bar or with POLARANG.
Object snap tracking	F11	Rest the cursor on a snap point for a moment, then move away: tracking lines run from it, so you can line a new point up with it.

With any of these showing a direction, type a length and press Enter. The point goes that far along it.

Grid and snap

The grid is a pattern of lines in the background, to help you judge sizes. Snap makes the cursor jump in steps.

Aid	Key	Command
Grid	F7	GRID sets the spacing, major lines and how it adapts as you zoom.
Snap	F9	SNAP sets the step.

LIMITS can mark the edges of your drawing area. With checking on, points outside them are refused.

The settings in one place

The Drafting Settings window (DS or OS) has a tab for each aid: snap and grid, polar tracking, object snaps, and Dynamic Input.

Command	Type	What it does
OSNAP	OS, DS, SE, RM, DDOSNAP, DDRMODES, DSETTINGS	Open the Drafting Settings: snap and grid, polar tracking, object snaps, dynamic input.
ORTHO	ORTHO	Turn orthogonal drawing on or off (F8).
GRID	GRID	Show or hide the grid (F7).
SNAP	SN	Set the snap spacing, or turn grid snap on or off (F9).
LIMITS	LIMITS	The drawing's limits, and whether points outside them are refused.
UNITS	UN	Set the display format and precision of lengths and angles (the Drawing Units dialog).

Measure what you drew

Command	Type	What it does
DIST	DI	Measure the distance and angle between two points, or along several (Multiple points).
ID	ID	Report the coordinates of a point.
AREA	AA	The area and perimeter of an object or of picked points (Arc, Length, Undo), with Add and Subtract running totals.
MEASUREGEOM	MEA	Measure Distance, Radius, Angle, ARea or Volume, or click objects in Quick mode.
LIST	LI	List the selected objects: kind, layer, space, handle, properties, geometry, area and perimeter.
MASSPROP	MASSPROP	The area, perimeter, bounding box, centroid, moments of inertia and radii of gyration of closed shapes.
CAL	CAL	Evaluate an expression: arithmetic, sin/cos/tan, sqrt, [x,y] points, dist, ang, vec, cvunit.
QUICKCALC	QC	The calculator palette: a number pad, scientific functions and unit conversion.

Next

• Learn the keys for typing at the cursor in Dynamic Input.
• Add sizes to the drawing in Annotation.