Import a picture to get dimensions from it


Roger T

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Roger, this is called "Photo Match" in SketchUp. The best set of instructions for doing this come straight from the SketchUp folks. Here is a link: http://sketchup.google.com/support/bin/answer.py?answer=94920

They give an example of how to make a model of a building, but the process is the same for a piece of furniture. What you will do is import a picture, then trace on top of it with lines and faces to create a model of the piece of furniture. Finally you can add some dimensions once you have a model.

Here are a couple suggestions that may be helpful:

1. Start with a decent picture. A couple different shots of the piece from a 45 degree corner angle are ideal. You want to see the corner and both sides if possible.

2. Be ready for some "educated guesses" about dimensions. You won't be able to exactly match the model to the picture dot for dot. For example, if you suspect that the top is 3/4" thick, then model it that way even if it looks slightly larger in the picture.

3. Importing a photo for "Photo Match" creates a new Scene Tab. You can always click on this tab to return to the "Photo Match" view. If you rotate the model you snap out of this mode, so use the tab to get back to the picture.

Hope this helps! If you want to share some pictures and describe what you are tring to do, I can try to give you some more help.

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I think "photo match" is an awkward and convoluted way to get information from a photograph. I just import the photo as an image, then scale the image to a known dimension. If you bring the image in before you draw anything you can do this with the Tape Measure tool to resize the model. (After you have some geometry in there this won't work as it will change the size of everything else as well. You can still resize the photo with the Scale tool, but you'll have to figure out a scale factor between what it measures, and what it ought to be.) Then I just use the photo as a reference, getting dimensions with the Tape Measure and drawing somewhere else in space. The point of view of the image makes a huge difference in how well this works. Most of the time, you can only get the photo sized for accurate dimensions in one axis at a time, and the perspective of the photo will throw things off. I end up making a lot of educated guesses based on relative dimensions between different parts. For example, you know that a top will overhang equally on both sides, but the photo won't measure that way due to foreshortening. If you have the overall length scaled accurately in the photo, you can subtract the length of the other stuff and divide by two to get an "average". That should get you close, but you could be off. Knowledge of the style you're trying to duplicate, along with common sizes and practices is essential.

The ideal situation is to take the photos yourself, doing the best you can to get a straight on shot from the front, side or top. There are some filters in PhotoShop you can use to stretch a photo to "square it up", but that's another piece of software and another set of skills. I keep meaning to do something more in depth about this, hopefully I'll get around to it.

Bob Lang

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All,

Thanks much for the help with this. I have some ideas floating around in my head, and am looking for just the right picture to bring into SU. I will give your suggestions a try, and if I fail miserably, I will be back with more questions.

Thanks again,

Roger

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