Keyholes — officially Aperture Passing — is where a lot of students burn time. You're shown a 3D object and five openings, and you have to pick the one the object can pass completely through. The trap is trying to rotate the whole object in your head. There's a faster way.
The core insight
The correct opening is identical to the object's outline (silhouette) from one viewpoint. So stop picturing the solid object tumbling through space. Instead, picture the flat shadow it would cast straight onto the wall of openings.
The object can be turned to any orientation before it passes through — but not during. So you only need one of its silhouettes to match an opening.
Three steps
- Find the three primary silhouettes. Picture the object's top, front, and end outlines. These are your candidate shapes.
- Compare to the five openings. Match each silhouette against the apertures.
- Eliminate by dimension. If an opening is too wide, too narrow, or too tall in even one direction, cross it off immediately.
Common mistakes
- Assuming the object must enter in the orientation it's drawn.
- Matching part of the object instead of its full passage.
- Missing tiny differences in width or curvature between openings.
- Checking only one silhouette instead of all three.
How to drill it
Strategy gets you started; volume makes it automatic. Generate keyhole questions until reading a silhouette is instant, and use the explanation to rotate the 3D object and confirm the matching view. Bump the difficulty as your eye sharpens.
Want the full breakdown, including a sample question you can try right now? See the DAT Keyholes section guide.