# How to Construct a Primary Auxiliary View given that an oblique surface with 6 sides

I need to construct the auxiliary views with the given front and right side orthographic views. The view is in third angle projection.

I observed that there is an oblique surface so that perhaps I need to construct here the secondary auxiliary view. However, I am confused in constructing those auxiliary views. I cannot make the oblique surface appear as an edge in the primary auxiliary view. I am stuck. Here, I already constructed the isometric view as my guide.

This is my outline for the construction of primary auxiliary view and I don't know what to do with the oblique surface and how to connect the points. My attempt is to use the fold-line method.

• Have you given us the whole question? Are there any clues missing from your post? Jul 19, 2021 at 17:14
• @Transistor thanks for the correction of my isometric view btw. I have a concern about constructing its primary and secondary auxiliary views. There is an oblique surface that I think I need to appear it as an edge in the primary auxiliary view. When I tried doing it, I cannot appear it as a single line or as an edge. That is where I am stuck to.
– Sigz
Jul 20, 2021 at 2:09

It's a tricky one.

Figure 1. Your isometric is missing this line.

Figure 2. A clue. The six-cornered shape is flat so it must be a plane going through these three points. Can you draw it?

Figure 3. The correct isometric view.

Figure 4. Slide 25 by Shelly Wilke on SlideShare. This and slide 9 may be instructive.

You did pretty well, but @Transistor is correct that the horizontal line needs to be extended. Maybe it looks like this. However, I don't think the inclined plane is correct as there will be another line (shown in red) to connect the corners.

• I had added in the >!  spoiler markup to your picture in case the OP still wants to work it out. It disappeared in your edit - I don't know if you had noticed it. There won't be a red line. See my answer which I generated with a plane split with OnShape. Jul 19, 2021 at 18:52
• @transistor I guessed it was your intent, but I know there is something wrong with my drawing, so I purposely leave it for further discussion. Let's wait and see.
– r13
Jul 19, 2021 at 19:00
• Thanks for the correction, but I have a concern with the six-sided oblique surface. I am struggling on how to make a primary and secondary auxiliary view because of it. Give me ideas on how to make it.
– Sigz
Jul 20, 2021 at 9:10
• I suggest creating the top view, then take projection on the inclined plane. Here are two articles that might help. skillscommons.org/bitstream/handle/taaccct/9338/…, ceet.niu.edu/faculty/kim/mee270/….
– r13
Jul 20, 2021 at 13:16