The 3D graphic below shows a set of goalposts similar to those used in the UEFA championship - Leaving Cert DCG - Question A-2 - 2016

Identify additional points that define the 3D dimensions of the goalposts. These include key heights and widths that correspond to the initial lines radiated towards the vanishing points. Make sure to align these points accurately to maintain realistic proportions.

With all points established, connect them to form the complete perspective drawing of the goalposts. Pay attention to angles, ensuring that they properly align with the perspective drawn so far. Finalize the sketch by refining the lines to represent the structure clearly.

For the back perspective, start by identifying the back vanishing point. Draw radiating lines from all relevant points of the goalpost's height and width towards the back vanishing point to ensure depth and proper alignment.

Draw a horizontal line at the top edge of the goalposts, ensuring it aligns correctly with the vanishing point established in the previous step. This line will set the height and define the upper boundary of the perspective.

Now, draw the bottom edge of the goalposts. This line should align with both the established perspective and the previously drawn top line, providing a realistic base for the structure.

Ensure your drawing is clean and well-presented. Use appropriate shading to enhance the 3D effect and highlight essential features. Optional annotations may be added to clarify the perspective lines or dimensions if necessary.