How to properly scale an image to actual size
To incorporated in my sketch as inches?
grab the tape tool.
click on one end of a dimension you know. click on the second end. type in the dimension you want. you’ll be asked if you want to resize
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For some reason I can’t get this true to scale.
Hello, explode your imported image first (right click > explode)
Why explode the image? There’s no need to do that to resize it.
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Also be aware that most images are pixel rasters, which means you have +/- 1 pixel potential error depending on where you click to measure the dimension.
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I do this often with plans / PDFs, and often I bring it into a drawing that may have other object in it.
Import Image or PDF.
Draw a line from 2 known points.
Make group of line and image.
Edit group.
Tape measure from one end of line to other.
Type dimension that the line should be.
Accept the dialog.
Exit group (or check dimension).
I will often choose my known dimension to be common in multiple imports so that I can use that as a reference when aligning the drawings / views.
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A couple small details to add to the above solutions:
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An imported image cannot be opened for editing, therefore your only option for resizing it with the tape measure tool will be to resize the entire model which will resize anything else you have in the model space. You can handle this by importing the image first into an empty file, where you can resize it as the entire model, then copy paste the correctly sized image into your master file. Or you can give the image it’s own context by adding a line to it and making them a group/component, or by exploding the image and making it a component. Once the image has it’s own context that can be opened then you can open it for editing and use the tape measure tool to resize and you have the option to resize only the active group or component.
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It’s a small point and perhaps obvious, but because of the mentioned inaccuracy of pixelated PDF or other image types its generally best practice to resize an image using the longest available known dimension. Then the two inaccuracies inherent in picking the end points of a fuzzy image represent a smaller percentage of the overall length. Whatever error you introduce with that one measurement will be spread across the entire resized image. Example. 1mm out on a 1cm measurement is a %10 error, 1mm out on a 10cm measurement is a %1 error.
You used to need to add some actual geometry but for the last two or three versions, you don’t have to. You can just create the group or component containing the image.
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Actually, what I’m trying to do is import this true to scale and pull these circular measurements off any advice how to do that?
there is no “true scale” in the file here.
maybe your image started as an A4 piece of paper. but when you scanned it, it became an image with pixels. sketchup has no idea how big a pixel should be in physical units. it’s like asking for the length of a rope.
when you import your image, IF you know the height or width of the actual image in the real wold, then you can immediately type it in. but unless you know the dimensions of the whole file, you’ll have to do it like we described, with the tape tool.
it takes like… a minute. even in a file in inches :
import the file in your inches / yard / whatever format file.
tape tool - one click, two clicks (I picked the biggest distance I know), type in the correct dimension + the correct unit, and BOOM it’s scaled correctly.
(the other are saying that you need to group your image first, true, unless your file is empty. if it’s empty, there is nothing around to be accidentally resized.)
once I’ve sized it correctly (using the existing dimensions on the image), I can draw or measure stuff.
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Same as I showed 3 hours ago.
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You’ve been shown several videos on how to do it.
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It only lets me scale one dimension. As soon as I set the correct length (11”), the width changes automatically. I need it to stay at 11” long and 8.5” wide. Why is this happening?
Well if you want your circles to be ovals you can scale it only in 1 direction. Do you want to scale the actual circles to be correct?
Your image does not have proportions to 8.5x11… I think it is anyone’s guess at this point what you want / need.
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Add the Unit and it will be an accurate size as specified and not a scale factor.
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I always forget that ! too bad i’m going to spend less time doing maths from now on
As @bmike points out, the aspect ratio doesn’t work for 11" long by 8.5" wide.
As the image opens at 300 pixels per inch:
Resized so the length is 11 inches:
Here’s the image at your desired dimensions.
I would have thought the rings are supposed to be circles, not ellipses.
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