(using all unique objects)
Because every view (front, back, side, top,…) is shown with perspective it can be very tricky to, for example look straightforwardly at a cabinet and extrude (push/pull) one of its sides down so as to be the same length as the side 8 feet away from it.
Is there a way to show different views without perspective?
Have a look at the Camera menu, and choose Parallel Projection (note that you can also toggle on/off the Perspective choice there in that Camera drop-down menu). Also useful to know is the ability to right-click on any face (make sure you’re inside the Group/Component levels) and select Align View to look directly at that face (works with section planes too).
[ Edit: I find it useful to create a key shortcut for switching from Perspective to Parallel Projection mode, as I do that often. You can assign custom shortcuts in Preferences > Shortcuts ]
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Thank you very much. One thing I can say for SketchUp is that forum response is incredible!
One thing that would make this easier is if the Views Toolbar (House icons) would (as is the case with Camera and Styles Toolbars) indicate the current selection by being greyed out.
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One thing to notice is that the name of the standard view you selected shows in the upper left of the window.
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My gosh, you’re right! (in tiny, tiny, tiny letters )
OK In Parallel Projection.
Now I can’t extrude the object left, right, up, or down (I can extrude it, it turns out, toward me or away from me: i.e., in directions I can’t (without extra viewports) control)
Sketchup is a 3d environment, the idea is you orbit around as you work. You can press the scroll wheel to orbit while still holding a tool.
So start pushpulling then orbit around so you can see where you want to go and finish pushpulling.
This works with all tools.
You should generally model in perspective and only use parallel Projection for setting images etc
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There will often be inferences that you can use as you extrude an object and they work in any view. If you are not moving with an axis or some other working relationship with the target object you can add guides to make a target. An intersection of edges or guides (or a guide and edge) is often the best inference to work to when you need to set something up. You can do this just as well or better in perspective view . A nice thing with pushpull is that whatever your orientation you can find an inference to stop using any point or intersection that is perpendicular to the extrusion at the correct distance(which lies in the plane of the face where it stops)
Obviously I’m not in a position to ARGUE with you, nor am I interested in doing so. I’m assuming that everyone who (graciously) responds to my posts knows SketchUp MUCH BETTER than I do—I defer to your expertise. However I am responding as an interested (fascinated, if you will) by the program, its capabilities, and its approach.
Though I may not be able to definitively and completely understand the repercussions of my questions, I hope I am able to clearly describe the situations that are making using the program difficult. I hope that in that regard my comments may serve as conduits to improving SketchUp.
My current problems, operating within a parallel perspective environment, are as follows:
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It seems incongruous to, in a parallel perspective environment, allow extrusions (push-pull) that only work in a toward-the-viewer/away from-the-viewer direction.
Alternatively, it seems precisely in keeping with the advantages of a parallel perspective environment, to allow movement and extrusions in directions one can observe on the screen. -
I understand that the extrusion problems I am facing may be able to be handled relatively efficiently in an iso… environment. However, in attempting to do so, within an even extremely simple situation (without multiple viewports—which I am NOT advocating)—the daunting effort required to select the bottom edge of a thin ‘plank of wood’; enable the push-pull tool and begin a push pull operation; the amount of mouse-wheel spinning action required to locate and reorient the endpoint location (or enable an inference point relative to that location) seems quite out of place when allowing the same action to be done, simply and directly, in parallel perspective without (or minimally) having to change zoom or pan settings.
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For all the advantages there are with moving through a more natural space, there is another confusion that arises in an iso-environment. Regardless of all the various useful views the program provides; and despite the ability to incrementally un-view components and layers (which very quickly becomes crucial) one must also struggle, in even the most minimally complex situations, with the obvious optical illusions that plague a partially to fully transparent view of isometric objects—a problem that doesn’t necessarily arise in a parallel perspective view.
You CAN push pull faces in other orientations than the parallel view. In this case I believe you a refering to faces oriented perpendicular to the camera angle The problem seems to be with selecting the face to pushpull. You can’t see it. So you cannot simply with a click begin the pull.
You can pre-select the face before you select the push-pull tool.
You can do that with a left to right selection window, selecting the edges and the face you wish to move --but how do you know you haven’t selected more than the face you want–or the wrong face? In this case the only answer may be to orbit slightly to see the face and select it, choose “Previous” under camera to take you back to the original parallel view (top, side etc.), then begin the push pull.
You must be correct, I’ll give up using this hopeless program immediately.
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This is not true. Push-pull works perpendicular to the individual face you are “extruding”.
Why are you sticking to Parallel projection? If you want to push pull upwards, you must be making at least a partially 3D model. (And yes, SU WILL pushpull up or down in top view, parallel projection, but as others have said, you can’t do it easily in the Top view - you need to orbit to view your plan at an angle.)
You are tying one hand behind your back if you don’t start to work in Perspective view. It’s the way SU was designed to work, with Parallel projection used for plan and elevation viewing and printing.
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Warning: one of my long essays follows. Skip if you are feeling TLDR;
It seems to me that the key thing to realize is that the traditional orthographic views are static. Working with pencil and paper, you choose an orientation and you are then stuck with it until you start a different view - in which you are immediately also stuck with whatever orientation you chose there. That means that, for example, if you chose a front view you can only see sides, top, and bottom as edge-on. If you want to do anything with those surfaces, even just look at them, you have to change to a different view. That’s why people who are well-versed in traditional orthographic drawing want multiple viewports on the screen at the same time. There is ambiguity about the nature of anything you are viewing edgewise. That’s also why in some of the posts here there is frustration or confusion about how to pushpull a face that isn’t square to the view: how can you grab a face that you only see edge on? Conversely, how do you know how far to pushpull a face when the motion is straight toward or away from you?
In SketchUp (and other 3D modeling tools), the view is not static. You can orbit, zoom, and pan to view your model from whatever orientation you want with no fixed commitment. You don’t need a side view to see that surface, you just orbit until it is visible. You can then pushpull it along the normal to that face, even if the normal isn’t straight in or out of the view. This is equally true whether you are using parallel projection or perspective. The only difference is the sort of geometric distortion you see in the view.
Parallel projection is good for surfaces that are perpendicular to the viewing direction or are in an isometric orientation, because distances on the screen view are scaled equally on the x, y, and z axes. Parallel lines look parallel too.
In situations where the only way to present your model is via static views, for example a printed proposal, orthographic views let the recipient take measurements and understand relative sizes easily. The entire presentation is static, so a projection that works well only for static views is appropriate.
But if you view the model from any orientation other than the traditional ones, these advantages are lost. Even in parallel projection, lengths are foreshortened unequally depending on their orientation to the view direction. The amount of foreshortening is the same for all distances from the viewpoint, which is very unlike the way we see the real world.
On the other hand, perspective projection corresponds to the way a real camera images the world and approximates what our eyes see. Parallel lines converge, causing non-uniform distortion of lengths depending on both the direction of the lines and how far they are from the camera. That makes it impractical to measure anything from a static view in perspective. As a result, though more realistic, traditionally perspective was used only for “artist’s rendering” of the model. This history makes many people reject perspective renderings as non-technical and more for eye-candy than for conveying details.
But again, this concept is tied to the view being static. When you can orbit, zoom, and pan, the impression in perspective view it is as if you are moving around the actual object (or moving the actual object in your field of view). Once you break the tie to orthographic thinking, perspective is intuitive and natural. Furthermore, in a 3D app such as SketchUp, you have measurement tools that allow you to easily determine the actual length of anything in the model without needing uniform scaling or a ruler.
On a technical level, there are also motivations to choose perspective due to how SketchUp manages parallel projection. These arose at least in part because SketchUp’s designers regarded parallel projection as a static presentation view, and perspective as the more natural working view while building a model.
SketchUp is lazy (and in some cases buggy) in how it manages the camera position in parallel projection. This is because in parallel projection, the distance from the camera to the model has no effect on the scaling of the model in the view. The projection lines are parallel to each other and perpendicular to the image plane. Move closer, move farther away, the view stays the same. To zoom in parallel projection, SketchUp changes the magnification of the view, not the camera position.
As you work on a model, it is easy to get the camera either too close or too far from the model. When too close, clipping occurs. Clipping looks highly unnatural in parallel projection! When too far, visual glitches such as z-fighting occur because the software can’t distinguish between positions whose distances differ by a small amount compared to their distance from the image plane. Both clipping and z-fighting occur in perspective as well as parallel. The difference is in how you can correct them.
Because zoom in parallel projection just changes the magnification, zoom-extents fits the entire width of the model into the screen by rescaling without moving the camera. As a result, in parallel projection zoom can’t fix issues that result from the camera distance. It doesn’t know that the issues are due to camera distance! So, once problems start to crop up, they persist.
Because in parallel projection SketchUp can’t on its own decide that the right fix is to move the camera closer or farther, it would be a useful feature to have a user-selectable command to make this happen.
In perspective projection, SketchUp handles zoom by moving the camera closer or farther from the model - just as you would do in the real world if you want to see smaller details or a broader view of an object. And yes, that causes the distortions from perspective to shift in the view - but in the same way as in the real world. So, zoom extents in perpective projection will usually repair the camera distance and create a “natural looking” view. I say “usually” because if a model is too vast or in some cases when the camera has somehow gotten to be looking at the other end of the universe, SketchUp can’t fix it without other user or extension actions to correct the underlying cause.
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Thank you Steve. Although as a visual artist and illustrator (not the guy who worked on AutoCAD interfaces) I understand what you’re saying and immediately appreciate the technical difficulties you’ve cited.
Mind you, I want to use SketchUp in the way it was intended, and (probably comes from my QA background) I’m quite the ‘sage’ at banging my head against the wall in trying and retrying…investigating…then trying and retrying something. But I’ve spent the last 20 minutes trying to select the top surface of a (planks of wood) box imbedded in another box to extrude it down so that the ends meet and:
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Though three (select) clicks selects the whole (imbedded/unique) box and hilites it in a way as to make it distinguishable from the others.
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(Select) And after finally (20 min! trying out different views and savagely clicking the escape key to start over, etc.)
a. Finally manage to triple click on the object and when I choose the push/p tool see all the highlighting go away.
b. Finally managing to select the top surface, choose p/p and, when I begin the extrude, I get the message “Offset limited to 0””
c. And then, in desperation, trying to select p/p and extrude ANY SURFACE of that object is non-responsive.
- All the while I’m running a second instance of SketchUp with a drawing consisting of nothing other than a box and finding that I can p/p by either
a. Selecting a surface and then using the p/p tool
b. Selecting nothing and then using the p/p tool to simply select and extrude
c. Hitting escape and simply using the p/p tool to select and extrude a different face or edge.
d. (I’m left wondering if maybe my 3 shelf-unit drawing is so complex that it takes minutes for a tool to recognize an edge or surface.)
And now, trying to figure out why two ¾” thick objects that meet and should appear the same size in projection aren’t the same size.
in a drawing imported in inch units
And then using the tape measure tool to double check the measurements and finding the parts have no dimensions at all.
Which probably means I have to start the whole drawing from scratch.
Everything about using your program is fantastic (and following your videos is an equally spectacular experience)
but using it for real life drawings is driving me up a wall
I can’t believe I’m the only one who’s had these problems.
How do you recommend I go about attacking this problem?
Can you share the skp file? If so, one of us can no doubt advise you specifically about how to proceed.
That looks wacky dimensionally, if I’m reading that right. It’s saying the total depth of the panel is only about 9/16" instead of something on the order of 10~12" (?), and if that’s the case, no wonder the thickness of the panel in immeasurably small (~0"). It also looks slightly off axis (not square)? If you could share the file, we could have more insight.
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Also, seeing the tilde in your dimensions usually means you have ‘display precision’ set too coarse, adjust that in Window/Model info/Units and untick Length snapping while you are there.
BTW Display precision doesn’t effect accuracy, just how it is displayed. The tilde telling you the dimension is approximate.
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Thanks.
I’m getting more used to using the program. I planned on sending the file in but not until I’d completely gone over it. I figured you guys deserved no less.
Just as soon as I thought I’d gotten to the final lap and was quick-checking dimensions with the tape measure tool—I found that, instead of returning either all exact or all approximate measurements, sometimes it returned exact measurements (3/4”) and sometimes only approximations (~ of course).
The drawing is basically very simple:
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Everything is 3/4” thick
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Side panels are 14 ¾” wide (lapping a ¾” back panel.
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Shelves should be flush with back and sides (i.e., 14” wide)
I spent a couple hours trying to get everything the same, to no avail.
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Now that I’ve set Display Precision to 1/64 I’m getting values like 1’ 2 21/32” and 1’ 2 15/64” and 1’ 2 5/32” on planks copied/pasted that should all be exactly 1’ 2 ¾”.
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Also shelves I’d extruded (even copy/pasted them so that they could function as a component!) so that they exactly met the front face of the side/vertical pieces (Although they seemed a component when I selected one and all were selected, they didn’t act like a component. I had to extrude each one separately!) I look at it from the other side and find that they’re ~27/64” from being flush on the other panel! Are the shelves wrong or are the panels they’re mounted on wrong? And if it is the vertical panel, is the wrong one the one on the right or the one on the left?
I expect that a good drawing should be able to be dimensioned and serve as a template for me to cut lumber to size. The way measurements are going, it will only serve as a pretty picture and I’ll have to redo all the work in situ.
Am I expecting too much of SketchUp? Is it actually just an impressive 3D display tool, generating impressive graphics but not capable of providing any dimensions a carpenter can take seriously?
I want to hang the shelves on adjustable standards/brackets on the existing shelves 
and route in grooves for these standards/brackets 
on the other. These details seem exactly what SketchUp is designed to do. But if it can’t get measurements right…
Well, back to work! I hope to be able to send something tomorrow.
Joost
There is no point struggling with something until you get it right, add what you have and we can point out what may be causing your issues.
You are attempting to model something well within sketchup’s capacity, But if you start with errors they will only compound as you go.