In third-angle (or first-angle) orthographic projection practice, the top, front, and bottom views align with respect to one another in which principal direction on the sheet layout?

Introduction / Context:
View alignment rules ensure that corresponding features line up between views so dimensions can be read across drawings without confusion. Knowing which views align vertically versus horizontally is fundamental.

Given Data / Assumptions:

• Standard multiview layout includes front, top (plan), bottom, right, and left views.
• Projection standard (first- or third-angle) affects placement but not the principle of alignment.
• We are asked about the alignment among top, front, and bottom views.

Concept / Approach:
In both first- and third-angle practices, the top and bottom views are placed above and below the front view respectively, keeping features vertically aligned so corresponding points lie on common vertical projectors.

Step-by-Step Solution:

Verification / Alternative check:
Open any standard projection diagram: vertical projectors connect features between top–front–bottom views.

Why Other Options Are Wrong:

• Horizontally: typically used to align front with right/left side views.
• According to the planar views / Parallel to the frontal plane: vague or irrelevant to alignment convention.

Common Pitfalls:
Mixing first- and third-angle placement; regardless of placement, alignment rules remain: top/front/bottom share vertical alignment.

Final Answer:
Vertically