Precisely positioning of objects

Hi there,
I am trying to place columns under this arch and am not sure how to go about doing this to achieve precise results rather than just doing it by eye.

If they are the same width use snapping to edges. Then just align them an axis at a time to the edge.

You can duplicate and move them a specific value, or separate that bit, use an array modifier, tweak to fit, then apply the modifier. Or create a face the length you want, subdivide it ‘x’ number of times and use it as a guide to copy them.

Quick video:

You should have started your array at the mid-point of the arch and used two arrays on the middle beam, going in opposite directions. This guarantees they will be exactly centered.

in layout mode drag the arrow out on the right of the colored rgb xyz under items your see transform
there’s location rotation etc etc

Indeed, yet another way to do it and as you say, depends if you want the posts based off the centre, sometimes though, you may want something else. It was more a case of showing multiple ways to attack the same problem, your double array is yet another. One thing I love about Blender, rare you are limited to a specific approach. :slight_smile:

Thank you everyone. Lots of great approaches. Much appreciated!

This is amazing. Thanks so much.

You’re welcome :slight_smile: I’ve a few videos on Blender on my channel, I try to cover just things people have asked me, as well as the occasional larger project.


Newbie question: could we just specify a horizontal centerline - say, y-axis - below the midpoint of the arch, array the columns in 1 direction - say, to the “left” on x-axis (even if that meant 1/2 of the center column); then just delete the “empty” half of the arch, & flip a mirror image to complete the symmetrical total assembly?
I get the (beginner’s) impression that a simple mirror-image command is not so simple?
In professional architectural design (Revit, even the cumbersome dinosaur AutoCAD), this has always been simple.
Mirror-image (or “opposite hand”) is a basic tool for real-world design for anything from furniture to entire new towns.
In SketchUp, for example, it is absurdly impractical.
Blender offers hope for architects, even though we in USA are shut out of making useful construction drawings in Blender, without our familiar foot/inch dimensioning.

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This sort of technique is used pretty much everywhere in Blender, a lot of time, you’ll see people create something, delete half and then go about building the remainder. Mirror and array combined make very effective tools.