Can't resize simple drawing

I have created a large rectangle with 1 small rectangle (same width) attached perpendicularly on one end with another similar one perpendicular 1/4" from the other one.
I am trying to set the first rectangle to 4.5" x 5" and the distance between the perpendicular rectangles to 1/4" spacing
When ever I use the measurement tool and measure the distances and then type in the new value, it prompts me if I want to resize. I say ok and it repositions the whole drawing and the size I set is set but all the other sizes readjust.
What is happening?
Also , for 3D printing, how do I determine how thick each plane will be?

Sounds like you’re using the wrong tool. If you want to move the end of the rectangle, select it and use the Move tool.

Individual faces have no thickness in SketchUp. You can make a face into a 3D shape with Push/Pull.

Upload the SKP file and we can give you a more complete answer.

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You were right, thanks.
Selecting move and grabbing the edge of rectangle did it. Putting in measurements beforehand made that easier too.shelft.skp (289.6 KB)

Here it is. I am intending to make a plastic shelf to hook on the top of my bathroom mirror to set wireless speakers on. Does this look right?

This is a start but it isn’t printable yet. You need to give the parts thickness. Are you planning to print it monolithically? How thick do you want the thing to be?

It looks like you might have moved only a corner and not an entire edge. Selecting the edge before getting the Move tool makes sure you are moving the edge.

yea still trying to figure out what moves when selecting what.
Added 16" thickness now…I think.shelft (1).skp (297.7 KB)

I’ve taken some liberties with the design but this should give you some ideas.


Front left to right.

  1. I drew a rectangle with the dimensions you show on your model. Push/Pull to give it thickness.
  2. A line parallel to the far edge divides the top face. Then Push/Pull to add the bit for the overhang.
  3. I drew in the outline of the front part of the hook to go over the mirror and added some gussets to stiffen the shelf.
  4. Push/Pull again.
  5. Then select the short horizontal edges at the front end of the gussets and use the Move tool to move them back down to the edge of the shelf. Then select all of the geometry, hit G to Create a component. Check in Entity Info to see that it reports as “solid”. Folling the exact steps I did results in a solid with no cleanup required.

FWIW, I’d be inclined to make things even thicker and make the hook over the mirror taller.

Maybe you mean 1/16 in.?

Do you want the slot for the mirror to be tapered? It is right now.

For something like this model, you would be better off to increase Precision in the Model Info panel.


Due to the way you added the geometry and moved things, you’ve got some internal faces which will prevent the thing from being considered solid and printable. You can edit the model to remove them but if you follow what I did, above, you can avoid the problem altogether. The key is to make the shelf 3D before you add the other details.

1/16" yea.
hmm, wow. Lot of things to consider.
Mirror is 1/4" or less. No taper.
Brace is a good idea.
Will consider this and start again I think.

Probably the best option. The model really isn’t that complex and it’ll be easier to start fresh and clean than to fix the current version.

FWIW, I’d be tempted to make the front part of the hook taller. You could cut away some of the middle of it without sacrificing strength. This would result in less material being used.

I’d also consider doing something to beef up that back part of the hook. As it is, there’ll be a stress riser in the corner which will make it likely to break.

All good points.
And for the record the speakers are plastic and weigh 1 lb 11 oz

Maybe something like this?

1 lb 11 oz isn’t a lot but you still might not appreciate it if the shelf breaks and the speakers come down on your noggin. :wink:

More great ideas with the top edges but the hook on back is too thick.
That wont fit and yet it makes me think I need to see exactly how much space I have between the mirror and the wall.
Yea these are really light speakers. Of course after I mount it I will be able to see if the overall thickness of everything is good before I put speakers on it.

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I wasn’t sure how much space there’d be behind the mirror so I was just kind of free thinking. It’s a good idea to check out the setting to make sure you have room to do what needs doing.