How to Sketch Stacked Plastic Trays With Sloped Faces and Center and Corner Drain Holes

Sketch the trays as one assembly: establish the stack’s outline, locate its sloped faces, then place the center and corner drain holes on their supporting surfaces. Keep unspecified details open.

The task is to preserve a particular arrangement of plastic surfaces and openings. A useful drawing should show how the trays overlap, which faces slope, and where the holes belong without supplying an assumed tray count, hole pattern, or hidden structure. The method below applies published drawing concepts to this task; the sources explain those concepts, rather than document this scene.

Establish what the drawing must preserve

Begin with a short visual inventory: stacked plastic trays, sloped faces, and drain holes in center and corner locations. Those features belong together in the same assembly. The description does not establish that every tray has an identical arrangement, that every corner contains a hole, or that the holes pass through the stack in alignment.

Keep three kinds of information distinct as you draw: what is specified, what is actually visible or clearly recalled, and what remains unresolved. For example, “plastic” is specified; a glossy finish is not. Center and corner locations are specified; their exact distribution among the trays is not. This distinction gives you a practical rule for deciding whether to add a mark.

Start with light pencil lines and enough space for the entire stack. Leave the surrounding area plain unless its contents are part of the available visual information. If an unresolved detail matters to understanding the drawing, use a brief note such as “hole shape unspecified” beside the relevant area rather than completing it by convention.

Block in the stack before drawing individual holes

Mark the assembly’s uppermost, lowermost, leftmost, and rightmost visible limits. Connect these lightly to establish its overall envelope. Then locate the major changes in direction along that outline. Work on the whole assembly before finishing one tray; otherwise, an early detailed section can leave too little room for the remaining forms.

Compare apparent widths, heights, and edge angles before adding small features. Marvin Bartel’s drawing instruction recommends using a pencil or ruler as a sighting aid to compare sizes and angles. When an object or reference image is available, use that approach to check the stack’s proportions. When working from recalled information, retain uncertainty instead of treating a measured sketch as a measured object. Drawing to Learn, by Marvin Bartel (https://bartelart.com/wp-content/uploads/2024/11/DrawingtoLearnDRAWING_MB.pdf).

Next, place the visible boundaries that distinguish one tray from another. Follow each boundary only as far as the available view supports it. Do not turn every horizontal-looking band into a separate tray: a band might instead describe a rim, a sloped face, or another visible part of the same form. Resolve its role by tracing where its edges meet.

Use the same viewing logic throughout the assembly. In perspective, parallel edges that recede toward a common vanishing point converge in the drawing; Autodesk’s perspective documentation describes this principle. Apply it only to edges that are actually parallel in the represented form. Sloping tray faces may introduce different edge directions. Perspective views — Autodesk Fusion (https://help.autodesk.com/cloudhelp/ENU/Fusion-Drawing/files/DWG-PERSPECTIVE-VIEW.htm).

For example, if the available view shows the stack from above and to one side, lightly establish its two principal receding directions before refining the trays. This is an illustrative construction choice, not a claim about the scene’s viewpoint. If that viewpoint is unknown, label a chosen view as a schematic reconstruction.

Show the sloped faces as surfaces with boundaries

A sloped face needs more information than a diagonal stroke. Locate the boundaries that define the face and show how they connect to adjacent surfaces. Ask where the slope begins, where it ends, and which part of it remains exposed between overlapping trays. Do not assume that the slope belongs to an outer wall, an interior face, or the floor unless the visual information establishes that relationship.

Draw the face’s outline lightly before applying tone. Check its apparent width at different points and the angles at its ends. If the surface is partly covered, preserve the visible portion and stop its boundary at the overlap. Completing the hidden outline with a solid line would give the drawing information that the view does not provide.

The spaces around the assembly can provide a second check on these angles. City Colleges of Chicago’s architectural drawing exercise defines negative space as the area where the object is absent and recommends examining it to reduce reliance on preconceived shapes. Negative Space Drawings — CCC Architecture (https://www.cccarchitecture.org/negative-space).

Apply that check selectively. Compare the wedge of background beside a sloped edge with the wedge in your sketch. Where an actual gap is visible between trays, compare its outline too. Do not introduce gaps merely to separate the layers on paper. If two boundaries are close together, a careful contour and a short label may communicate the relationship more faithfully than added space.

Locate center and corner holes on the correct faces

Before outlining a hole, identify its supporting surface. A hole in a sloped face must be positioned within that face; a hole in another surface must be located relative to that surface’s boundaries. The center of the entire drawing is not a useful substitute for the center region of the relevant tray surface.

Use two nearby references for each location. For a center hole, compare its position with opposing boundaries of the supporting face. For a corner hole, compare it with both edges that define the relevant corner. Check whether the opening sits inward from those edges or intersects a boundary, but record either condition only when established.

Do not automatically place a central opening at the halfway point of the face’s apparent width and height. Perspective and the face’s shape can make that screen-space midpoint a poor guide to its physical center. If a rectangular supporting face is established, light corner-to-corner diagonals can help locate its projected center. Use that construction only for the appropriate geometry; do not impose a rectangle on an unspecified surface.

Keep location and shape as separate decisions. The term “drain hole” does not establish a circular opening. If circularity is known and the surface is viewed obliquely, an ellipse may be a suitable drawing construction. Autodesk documents the use of ellipses to represent circles on oblique isometric planes and describes their two axes. This supports the construction technique, not an assumption about these holes. To Work With Ellipses — Autodesk AutoCAD (https://help.autodesk.com/cloudhelp/2020/ENU/AutoCAD-Core/files/GUID-A3E54913-3813-407D-9283-19EC6610D4F3.htm).

For an illustrative circular opening, first mark its position, then its apparent long and short dimensions, and finally its contour. Compare its orientation with the supporting face. If the opening is partly covered, draw only the visible portion. Avoid copying a complete oval onto every tray or into every corner; that would introduce a pattern the description does not supply.

Keep openings, overlaps, and plastic surfaces legible

Give each line a clear purpose: an outer contour, a boundary between surfaces, an opening edge, or a temporary construction guide. Strengthen the confirmed contours gradually. Remove construction lines that could be mistaken for extra rims or holes, while preserving any notes needed to explain unresolved geometry.

At an overlap, trace the boundary of the nearer surface and interrupt the covered boundary. Do not continue a rear edge through the foreground tray simply to show that another layer exists. Instead, use its remaining exposed edges to establish its position. This keeps the assembly readable without inventing a transparent material.

Treat the plastic finish as an independent detail. If color, sheen, transparency, or surface texture is unknown, leave it unspecified. A plain contour drawing with a “plastic trays” label can preserve the supplied material information. Added highlights, repeated texture marks, or see-through walls would each make a further visual claim.

Tone is optional. If lighting is available in the reference, follow it. If you use light shading solely to distinguish adjacent planes, label it as diagrammatic shading. Likewise, do not fill every opening with solid black by default: where the view establishes a visible surface beyond a hole, preserve that visible relationship.

Check the assembly from outside to inside

Review the sketch in the same order that its geometry was built. This diagnostic sequence helps locate the source of an error before you redraw a small feature:

1. Check the outer envelope. Does the stack have the intended overall proportions and edge directions?

2. Trace the tray boundaries. Can each visible layer be followed without turning a rim or face into an extra tray?

3. Inspect the sloped faces. Do their boundaries connect coherently, and do they stop where covered?

4. Check each hole’s supporting surface. Is its location tied to that face rather than to the page?

5. Compare center and corner relationships. Have you added symmetry, repeated openings, or hidden alignment without evidence?

6. Review material marks. Do they record established appearance, or add an unsupported finish?

If a hole looks misplaced, check the face beneath it before moving the opening. If the stack seems flattened, inspect overlap boundaries and exposed face widths before adding darker shading. If the result looks more regular than the available information, remove unsupported repetitions rather than refining them.

Finish when the drawing communicates the connected structure: plastic trays stacked together, their sloped faces, and center and corner drain-hole locations. Retain the visible relationships and label meaningful uncertainties. A clear record can leave details unresolved while still making the assembly understandable.

Sources

• Drawing to Learn — Marvin Bartel (https://bartelart.com/wp-content/uploads/2024/11/DrawingtoLearnDRAWING_MB.pdf)

• Perspective views — Autodesk Fusion (https://help.autodesk.com/cloudhelp/ENU/Fusion-Drawing/files/DWG-PERSPECTIVE-VIEW.htm)

• Negative Space Drawings — CCC Architecture (https://www.cccarchitecture.org/negative-space)

• To Work With Ellipses — Autodesk AutoCAD (https://help.autodesk.com/cloudhelp/2020/ENU/AutoCAD-Core/files/GUID-A3E54913-3813-407D-9283-19EC6610D4F3.htm)