Studio Matrx Monthly · Volume 1 · Issue 2 · July 2026
Amogh N P
✦ In loving memory of Amogh N P — Architect · Designer · Visionary ✦
A close-up of a computer screen showing a detailed CAD floor plan being drafted — clean walls, doors and furniture outlines in progress, a mouse and stylus beside the keyboard, warm light, no people, no legible text.
Unit IIComputer Studio I

The 2D Drafting Toolkit

Draw, modify and place exactly — the heart of the course.

≈ 55 min + drafting practiceByAmogh N P· Architect & interior designer

Everything in a 2D interior drawing is built from a small vocabulary of commands used as decisions, not buttons. Learn the draw commands and the crucial LINE-versus-POLYLINE distinction; the modify commands, with OFFSET as the interior workhorse and FILLET-at-radius-0 to close a corner exactly; the precision tools that place points precisely; window-versus-crossing selection; and the discipline of drawing accurately at 1:1, never eyeballing.

Learning objectives

By the end of this lesson, you will be able to — mapped to the course outcomes for Computer Studio I:

1
CO2 · Understand

Choose the right draw command, and distinguish LINE from POLYLINE.

2
CO2 · Apply

Use the modify commands — especially OFFSET, TRIM and FILLET — to build and clean geometry.

3
CO2 · Apply

Place points exactly with object snaps, tracking and direct distance entry.

4
CO2 · Understand

Distinguish window from crossing selection and draft with construction discipline.

Create, then shape

Draw & modify commands

The draw kit (and why POLYLINE beats LINE for outlines), the modify kit with OFFSET and FILLET-0, and why concept-first teaching survives a version change.[1, 2, 3]

Draw commands: create the geometry LINE (L) separate segments PLINE (PL) ONE object, straight + arc CIRCLE (C) RECTANG (REC) ARC (A) Prefer POLYLINE for outlines — a room boundary you can offset and measure as ONE object. This is one of the most useful early insights. Commands are decisions, not buttons: choose the tool that expresses your intent exactly.
DiagramThe draw commands — line, polyline, circle, rectangle, arc, polygon — and the key line-versus-polyline distinction
Modify commands: shape & multiply OFFSET parallel copy (walls!) TRIM cut to a boundary FILLET 0 clean sharp corner MIRROR ARRAY tiles, chairs round a table OFFSET is the interior workhorse; FILLET at radius 0 closes two wall lines exactly. SCALE changes TRUE size — never use it to “scale for the plot”.
DiagramThe modify commands — offset, trim, fillet, mirror and array — the interior favourites

Create the geometry

A small set builds everything. LINE (L) makes separate straight segments; POLYLINE (PL) makes connected straight-and-arc segments as ONE object with a width — prefer it for outlines you'll offset or measure. CIRCLE (C), ARC (A), RECTANG (REC, a closed polyline), ELLIPSE (EL) and POLYGON (POL) complete the kit, with XLINE/RAY as infinite construction lines and SPLINE for freeform curves (use sparingly in working drawings). The LINE-versus-POLYLINE insight is one of the most useful early lessons.[1, 2]

Place points exactly

Precision, selection & discipline

Object snaps and tracking, direct distance entry, window-versus-crossing selection, and the construction discipline of true geometry and clean junctions.[1, 4]

Object snaps: never place a point by eye ENDpoint MIDpoint CENtre INTersection OSNAP snaps the cursor to exact points on existing geometry, so corners meet corners — never “close enough.” Two lines 0.3 mm apart break hatch, area & dimensions. Plus ORTHO, POLAR & snap-tracking to place points precisely.
DiagramObject snaps place the cursor on exact points — endpoint, midpoint, centre, intersection, perpendicular
Selection: direction changes the result Window (drag left → right) selects only objects FULLY enclosed (the small square) Crossing (drag right ← left) selects anything it TOUCHES or encloses (both) STRETCH needs a crossing selection; window is safer for precise picks.
DiagramWindow selection dragged left to right selects only fully enclosed objects; crossing dragged right to left selects anything touched

Never place a point by eye

This separates a drafter from someone pushing lines around. OBJECT SNAPS (OSNAP) snap the cursor to exact points on existing geometry — ENDpoint, MIDpoint, CENtre, INTersection, PERpendicular, TANgent — so corners meet corners exactly. ORTHO (F8) locks to horizontal/vertical; POLAR TRACKING (F10) snaps to preset angles; OBJECT SNAP TRACKING (F11) locates a point aligned from two others without construction lines. Grid and snap help modular work. Use them always — never 'close enough'.[1]

Commands are decisions

Try it — the toolkit explorer

Filter by Draw, Modify or Precision and pick a command to see what it does and when to use it.

Toolkit explorer · commands are decisions, not buttons

LINE

alias: L

Draw

What: A series of straight segments — each one a separate object.

When: Quick single lines. For outlines you'll edit as a unit, prefer PLINE.

Real AutoCAD command names — but the concept (what it does, when to use it) survives any version or tool change.

Myth vs reality

At a glance

AspectOne sideThe other
LINE vs POLYLINELINE: separate segmentsPOLYLINE: one object, offsets & measures as a unit
Placing a cornerMyth: eyeball / drag it closeReality: snap to the exact endpoint (OSNAP)
Window vs crossingLeft→right: fully enclosed onlyRight→left: anything touched (STRETCH needs it)
SCALE commandMyth: use it to set 1:50Reality: it changes true size — scale is at output
OFFSET vs COPYOFFSET: parallel at a distanceCOPY: a free duplicate anywhere
Vocabulary

Key terms

LINE vs POLYLINE

Separate segments versus one connected object (with width) — prefer PLINE for outlines.

OFFSET

A parallel copy at a set distance — the interior workhorse for walls and borders.

FILLET (radius 0)

Rounds a corner — and at radius 0 closes two lines to a clean sharp corner.

Object snap (OSNAP)

Snaps the cursor to exact points on geometry — the core accuracy tool.

Direct distance entry

Aim the cursor and type a length — the fastest accurate way to draw a known distance.

Window vs crossing

Left-to-right selects fully-enclosed; right-to-left selects anything touched.

Apply it

Practice task

Write the command sequence to draft a simple room: a rectangle for the inner face, OFFSET outward by the wall thickness (say 230 mm), then TRIM or FILLET-0 to close the corners cleanly, and MIRROR a door block to the opposite hand. Name the object snap you would use at each junction, and explain why you never “eyeball” a corner and never use SCALE to set the plot ratio.

Check your understanding

Self-assessment

1. To draw a room outline you can offset and measure as one object, use —

2. The interior 'workhorse' command for wall thicknesses and borders is —

3. A crossing selection (dragged right-to-left) selects —

In a nutshell

Recap

Build drawings from a small command vocabulary used as decisions — and prefer POLYLINE over LINE for outlines.
Modify with MOVE/COPY/ROTATE/SCALE/MIRROR and the interior favourites OFFSET (parallel copies) and FILLET-0 (clean corners); ARRAY for patterns.
Place points exactly with object snaps, ortho/polar tracking and direct distance entry — never by eye.
Window selection (left→right) takes fully-enclosed objects; crossing (right→left) takes anything touched, and STRETCH needs it.
Draft with construction discipline — true 1:1 geometry and clean junctions, verified zoomed in.
The evidence

References & further reading

  1. [1]Autodesk, AutoCAD Help — 'Draw Objects', 'Modify (Change) Objects', 'Use Precision Tools / Object Snaps', 'Select Objects'.
  2. [2]George Omura & Brian C. Benton, Mastering AutoCAD and AutoCAD LT (drawing/editing; osnaps, tracking, direct distance).
  3. [3]Ellen Finkelstein, AutoCAD and AutoCAD LT Bible (command-by-command draw/modify and selection).
  4. [4]Beverly L. & James M. Kirkpatrick, AutoCAD for Interior Design and Space Planning (the toolkit applied to walls and furniture).

Further reading

  • George Omura & Brian C. Benton — Mastering AutoCAD and AutoCAD LT.
  • Ellen Finkelstein — AutoCAD and AutoCAD LT Bible.
  • Kirkpatrick — AutoCAD for Interior Design and Space Planning.

Sources gathered and fact-checked June 2026. Published values vary by source, sample and method — treat as indicative and confirm against the cited standard before structural use.

A

The author

Amogh N P

Architect, interior designer, and creative polymath. Studio Matrx began in his notebooks — his vision of design made honest, useful, and open to everyone. Its Academy is written and taught in his memory, and free, forever.

More about Amogh →