Free printable resources · Original practice
Orthographic drawing exercises.
One model, three views.
Turn 12 original block models into front, top and right views. An explicit height plan removes hidden-cube guesswork; each solution shows the exterior silhouettes.
12 models.
Third-angle layout.
Silhouettes & footprints only.
More ways to practice
Project occupancy, then check shared extents
Fix the axes first. Let x run left to right, y run front to back, and z run bottom to top, with one unit cube per cell. A front view looks along y, so its horizontal coordinate is x and its vertical coordinate is z. A right view looks along x, so its horizontal coordinate is y and its vertical coordinate is z. A top view looks along z, so its horizontal coordinate is x and its vertical coordinate is y.
For each view, mark a cell as filled when at least one cube occupies the line of sight through that cell. This produces an occupancy silhouette. It does not tell you whether an internal edge would be visible or hidden in a finished line drawing, so keep those claims out of the exercise unless the model itself defines them.
- Write the axis convention and unit at the top of the sheet.
- List every occupied cell as an ordered triple (x, y, z).
- For the front view, collect each distinct (x, z) pair.
- For the right view, collect each distinct (y, z) pair.
- For the top view, collect each distinct (x, y) pair.
- Draw each silhouette on its own grid and label the viewing direction.
- Compare the x extent in front and top, the z extent in front and right, and the y extent in right and top.
A second worked model with a deliberate notch
Use eight unit cubes: six fill a 3 by 2 base at z = 0, with x = 0, 1, 2 and y = 0, 1. Add two cubes above the left column at (0, 0, 1) and (0, 1, 1). The total volume is eight cubes.
The front view looks along y. The occupied (x, z) cells are (0, 0), (1, 0), (2, 0) and (0, 1), giving an L silhouette three units wide and two units high. The right view looks along x. The occupied (y, z) cells are (0, 0), (1, 0), (0, 1) and (1, 1), giving a two by two rectangle. The top view looks along z. All six base cells appear, giving a three by two rectangle.
Check the shared extents: front and top both span x from 0 to 2; front and right both span z from 0 to 1; right and top both span y from 0 to 1. These agreements are necessary but not sufficient for a correct drawing, so also confirm that each silhouette was built from the cell list rather than copied from a neighbouring view.
- Mark the eight occupied cells on a simple grid before drawing any view.
- Derive the front silhouette from distinct (x, z) pairs only.
- Derive the right silhouette from distinct (y, z) pairs only.
- Derive the top silhouette from distinct (x, y) pairs only.
- Record the three extents and compare the shared axes.
- Label the projection convention used on the sheet.
Diagnostic checks for the extension task
A common failure is mixing axes between views, especially using x as the horizontal coordinate in the right view. Another is drawing a rectangle where the cell list gives an L shape because a column was overlooked. A third is treating an occupancy mask as a complete line drawing and adding internal seams that the model does not define.
Use a short written audit after drawing: list the distinct coordinate pairs for each view, count them, and compare with the drawn filled cells. If the counts differ, the drawing and the cell list disagree. Keep the audit on the page so a reader can follow the reasoning without needing a separate answer key.
- Re-list the distinct coordinate pairs for each view after drawing.
- Count filled cells in the drawing and compare with the list.
- Check that no view uses the wrong horizontal axis.
- Confirm that internal seams are not asserted beyond the occupancy data.
- State the projection convention and unit beside the drawing.
Reading the result without overclaiming
Orthographic exercises have multiple valid presentation choices, such as line weight and label placement, so judge the reasoning and consistency rather than a single exact picture. The occupancy method is a teaching aid for relating a defined model to three views. It is not a clinical anatomy method and not a substitute for engineering or construction documentation.
- Compare each view against its own coordinate list.
- Check the three shared extents.
- Confirm labels and units are present.
- Note any unsupported hidden-line claim.
Try this example
A model has eight unit cubes: six at z = 0 covering x = 0, 1, 2 and y = 0, 1, plus cubes at (0, 0, 1) and (0, 1, 1). Find the front, right and top occupancy silhouettes and check shared extents.
Show the worked explanation
Front view along y: distinct (x, z) pairs are (0, 0), (1, 0), (2, 0) and (0, 1), an L shape three wide and two high. Right view along x: distinct (y, z) pairs are (0, 0), (1, 0), (0, 1) and (1, 1), a two by two rectangle. Top view along z: distinct (x, y) pairs cover all six base cells, a three by two rectangle. Front and top agree on x from 0 to 2; front and right agree on z from 0 to 1; right and top agree on y from 0 to 1. The total volume is eight cubes. These checks cover occupancy and dimensions only, not hidden internal seams.
Common mistakes
- Using x as the horizontal coordinate in the right view. For a right view looking along x, use y horizontally and z vertically, then rebuild the silhouette from (y, z) pairs.
- Drawing a full rectangle where the cell list gives an L shape. List distinct (x, z) pairs for the front view and mark only those cells before drawing the outline.
- Treating an occupancy silhouette as proof of visible or hidden internal edges. Limit the drawing to filled cells and dimensions, and label any internal seam as undefined by the occupancy data.
Check your work
- The viewing direction, projection convention and unit are stated.
- Each view is derived from its own distinct coordinate pairs.
- The front silhouette is an L shape three units wide and two units high.
- The right silhouette is a two by two rectangle.
- The top silhouette is a three by two rectangle.
- Shared extents agree: x in front and top, z in front and right, y in right and top.
- No hidden or visible internal seam is claimed beyond the occupancy data.
- The drawing is presented as a teaching exercise, not a manufacturing or construction specification.
Questions before you start
What does an occupancy silhouette show?
It shows which grid cells contain at least one cube along the viewing direction. It does not by itself establish which internal edges would be visible or hidden in a finished line drawing.
Why compare extents across views?
Shared axes must agree. Front and top share the x extent, front and right share the z extent, and right and top share the y extent. A mismatch signals an axis or cell-list error.
Is this a manufacturing or construction specification?
No. It is a teaching exercise about projection and view correspondence. Do not use it as a fabrication or construction document.