Relationships between objects

I’m working on my first design where I need to put one box on top of another. (Beam on top of post). The different boxes can be adjusted to different sizes

  • I would like the bottom center of the post to be at 0,0,0
    • The height of the post does not change, it’s fixed at 16”.
  • I would like the bottom center of the beam to sit on the top of the post, and centered.
    • The length of the beam does not change, it’s fixed at 17”.

Mid-Beam Cap (11.2 KB)

I can adjust the dimensions of the Post and Beam, but just need help getting them in the right space. Would anyone mind having a look at the attached file and letting me know what I’m missing?

Mid-Beam (8.4 KB)

It makes no sense to supply vectors to the Box ‘B’ (Base Plane) inputs. I used domain boxes instead of center boxes. Domain input expressions are “-x/2” and “x/2”.

1 Like

You used box from center which give you box scaled twice.

Mid-Beam Cap (16.8 KB)

This is supremely helpful! As a new user, I never would have figured this out on my own. Would you be so kind as to help me with another? What would I need to add to force the beam to connect to the post like this?


This is one possibility. The expressions on the beam Box 'Y’Domain inputs have changed, can you read them? ‘A’ is “-x” and ‘B’ has no expression, just ‘Length’ minus half the post width.

Mid-Beam (9.3 KB)

It’s important to understand every detail…

Thank you Joseph! With the information that you have provided here, I should be able to figure it out for the other shapes that I need.

Well, if I understand you correctly, it might be a little more confusing than you think… it confused me!

Your beams are 7" wide and the post is 5" wide? Beam A is centered on the post but Beam B is not?

Mid-Beam (17.6 KB)

You might be better off defining the beams directly, “on the ground” at the origin, and then moving them into place? The Domain Box can get confusing when used for positioning like this.

There is no single correct method, it depends on the objectives and work flow.


FYI, because I built the model carefully, notice what happens when I move the base construction plane XY by assigning a point to its input where X and Y are set to ‘post width / 2’: