SketchUp Make question

[Richard Sextro]

I have recently started using SketchUp for designing an entertainment center (based in part on some designs and techniques I found here on SMC). I've found the learning curve to be very steep - partly because I had to unlearn the stuff I used to know for 2-D programs like MacDraw and Canvas, etc. Nevertheless, this is a really powerful tool and now that I've clawed my way some of the way up the learning curve, I'm really very impressed by what it does and what I can do with it. However, one of the things I can't seem to figure out how to do is to resize an assembly (like a cabinet) without using brute force. BTW, I'm using SketchUp Make (2013 version) on a Mac (running OS 10.9).

To be a bit more specific - I have a fairly complete design for an EC that includes a base cabinet that will hold the flat screen TV and the A/V components, etc. and then two side shelf units that attach to the center cabinet, plus a bridge cabinet across the top (the design borrows heavily from two designs in Woodsmith magazine). My wife and I made a 'blue tape' outline of the whole EC on our living room wall and found that the design is really too wide - hence a need to reduce the overall width. The only way I can see to do that is to go back into the side shelf unit and 'pull it apart' (electronically) and then resize each piece of wood that figures in to the overall cabinet width. Since I used SU to mock-up some of the construction details (e.g., dado and rabbet joinery, etc.) - thinking it would let me make a cut list and construction drawings - resizing each piece is a multistep process and a bit of a pain in ... So did I miss something or some feature in SU that would let me do this with one mighty button push or ? I do know about the rescaling feature, but that won't work (as far as I can tell) because it rescales everything proportionally - so things like dados, etc. get messed up.

Having said that resizing each piece is tedious, for those pieces that are essentially rectilinear slabs (e.g., a plywood shelf), reducing the length is pretty easy (using something called the Push/Pull tool). However, if the piece has curved elements - like, say, a stretcher/apron that has an 'S' curve on either end - one cannot simply make the piece shorter/longer by 'pushing/pulling' on one end. In fact, the only way I can see to do it is to literally 'cut' the stretcher in half and resize the middle portion where all the lines are straight/parallel. Soooo - have I missed something or ?

Despite the question, SketchUp is really quite slick - especially because it has allowed me to work up and print out different views (3-D projections) as I was pulling the EC design together for review and approval of the SDC (spousal design committee). We're now on version 4.0...

Sorry for the long post. Any help/insights/commiseration would be appreciated.

- Rich

[Dave Richards]

Rich, I'll send you a PM with an answer to your question.

[Alan Caro]

Richard Sextro,

It is relatively easy to change the proportions of objects in Sketchup. In the case of wanting to change an Assembly or object in only axis, the Extrude (Push/Pull) works and can be used for accurate re-dimensioning or you can use the Scale command to alter by one or all axes at once and to an accurate proportion. I tend to use Scale more often because I can select only one axis, two, or all three.

To use Scale > (Sorry if this description is surplus to need- skip to below) Click on the Selection Tool - the arrow. Select the entire cabinet by using the mouse to draw a box around the whole drawing. All the lines should be highlighted blue. On the Menu Bar at the top go to Tools > Scale. The A 3D box will appear around the cabinet with small green boxes at the corners, the center of the top and bottom, and the center-lines of each side. If you want to alter only the length, you can click on the center box on the short side of the selection box and pull parallel away from the center of the object and everything will be proportionally lengthened. To increase the height, pull on the center box of any of the top edges. If you want to increase everything in all dimensions, you can pull on any of the corner boxes. To increase by an exact amount > Notice in the lower right corner a small window marked Scale. If you calculate the new size, Say you want to make the 4' cabinet to be 6' long, you can select the center box on the short side and while pulling it in length, watch the number in the lower right box until it reads "Green, Blue" - or which ever axes are affected- and "1.5". Of course the entire object may be scaled in all directions be pulling at a corner green box until you have the proportion of increase you want. As mentioned, in some case where you may want to use Extrude and other times> Scale.

Sketchup_Scale screen_2.21.14.jpg

As Dave Richards (thanks Dave) points out, Scale will alter critical thicknesses and angles. However Scale is still the correct way (well, I don't know of another) to alter assembly dimensions, but there will be a rescaling of the critical dimensions necessary. This rescaling has to do with the axes - the direction(s)- that the assembly is rescaled. If you alter the length, only then the thicknesses in the width will be altered to the same degree, if the entire project is altered, all the dimensions alter proportionally. The way to maintain certain dimensions is to make each piece a "Group" (Edit > Make Group). Rescale the assembly and then rescale each group in the direction that has needs to remain as original. You can verify the dimensions by using the Tape Measure tool. I've done assemblies too where I make a group of a sub-assembly, remove the sub-assembly, rescale the overall object and then replace the sub-assembly. For example, with a 3D model of a keyboard instrument, the keyboard /action is made a Group, I pull that group out to the side, resize the case, rescale the case scantlings and some structural elements to the original thicknesses, and then replace the keyboard action. The case is wider /longer, but the keys and action and the case thickness are in the original dimensions. On your project, if you have curved details such as scrolls /profiles cutouts, joinery, or mouldings that you don't want to stretch in on direction or another- that need to remain the same- make them a Group that you can unplug and set aside, and then plug back when the overall assembly is resized.

This reads as more complicated than it is. I would suggest trying it out before altering your drawing. Using the rectangle tool to make a rectangle of a certain size, extrude it to a certain height, and extrude each side (push inwards) to a 1" thickness. Make each of the 6 sides a Group. Select the resulting box in a window and just try the Tools > Scale and click and click/pull on the various yellow boxes ("grips") and try the exact scale command to make the box 1.5 X. After, use Scale or Extrude to adjust each Group (side) back to a 1" thickness by scaling in the appropriate axis (=equals the thickness) to .75.

Another aid to checking this kind of work is to use View > Face Style > x-ray and you can see everything inside and out together.

Alan Caro


TBase_ Mockup_whole_Tl_11.24.10.jpg Sketchup Test_Entry Door an dLiving Room 75.jpg

[Bob Lang]

I move some parts and "stretch" others. It can get tedious, but it avoids the issued introduced by the Scale tool. I wrote about this on the Popular Woodworking blog a few years ago, you can find it by searching "Changing and Stretching With SketchUp"

Bob Lang

[Sam Murdoch]

Using the scale tool can be frustrating until you figure out where to grab in order to move in one or two orientations without changing all. Alan offers a few good tips for using the scale tool successfully. I also have trouble with scale because it scales in percentages rather than in increments of an inch. I work around this by adding dimensions to my drawing before scaling and then as I scale I just watch for the dimension to get to the size I need. This might make Dave and Bob laugh but I admit that it is a work around that works pretty good .

[Alan Caro]

Richard Sextro,

Restating /clarifying my earlier reply, in my experience the best approach to alterations is to make each part a Group or a named Component, and if the project is quite complex, place Components on Layers. If there are portions of a group that need to remain the same such as profiles, cut -outs of a certain shape of size, moldings, scrolls, designs, make these a Group or Component. Components are useful because repeated elements are all automatically updated when edited. If you are doing large, complicated project, layers are useful as they can be turned off to make navigation easier. When a Sketchup model is more than about 20MB, the navigation can become very slow even on a quite fast computer. I'm working on a 45MB model and I have to wait a painfully long time to move around the model unless I turn off the layer with the 340 trees on it and view in monochrome.

When altering Groups or Components there will be circumstances where using the Push /Pull tool will be appropriate as the piece can be stretched one axis at a time, and as Sam Murdoch mentions, in Push /Pull, can be done by dimension- easier than calculating the proportion. Scale is useful because it's possible to try out the forms by changing more than one axis at a time and there are times when multiple sizes of pieces are best when maintaining the same proportions. Mouldings, table and chair legs, scrolls, pediments, and finials anyone? In either Push / Pull or Scale, having the part that needs to maintain proportions be a Component means something may be stretched, but the component will not change. The hierarchy of Group has to be considered for this work, details should be a group enclosed by the larger whole piece enclosed in an assembly group. If you lengthen a shelf that has a molding on a long side by Push /Pull, the molding will not be altered, but if you widen the shelf, the molding will be stretched horizontally unless it is a Group within the shelf Group (or Component within a Component) in which case the shelf will be wider -without changing the thickness- and the molding will have the same curves and steps.

This again is starting to sound a bit complex, but the important feature is to make every part and important feature into a Group or Component and nest the Groups or Components according to whether they are details or assemblies.

Alan Caro

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