Trouble pushing/pulling a face of an imported STL file


I am working on a part for an RC airplane - the canopy for the plane. I have imported an STL file for the canopy into Sketchup; it’s a reasonably complex shape (different curves), but there is a small modification I would like to make for it. Essentially, there is a place in the shape where I would like to make a rectangular “compartment” about half its current height (making it more shallow – imagine a shoebox that you want to squish down to make it a flatter/shorter box).

The problem is, I can’t simply pull/push the surface I would like to move to “squish” the rectangular compartment. I can select the entire shape, and with some effort I can select the components of the particular face with the push/pull tool, but I am not able to move the surface to achieve the desired effect. Any guidance would be much appreciated.


It’s hard to imagine withput an image (or the model, or a link to the stl, or…).

Complex shape with different curves sounds like uneven faces, which can’t be push-pulled with the standard push-pull-tool. Maybe the plugin JPP (joint push pull) by Fredo6 can help here, but you should upload additional information to help us to help you more…


If the ‘rectangular compartment’ has a flat bottom, but curved or sloping side, you might be able to select the bottom face(s) and just Move the face(s) to make it shallower.

If you were to upload an STL or SKP file of the issue, you could get more practical and focussed help.


Here is the stl; the area I am focused on is the recangular “box” at the nose. Clearly it is a complex shape, as it is connected to curved and irregular surfaces. My desire would be to make it about half as deep (the stl shows the canopy pointing up vertically - by “shallow” I mean reducing the shortest axis by 50%), and likely to cut off the “nose” of the overall canopy by a couple of centimeters.

Also, thank you for responding. I’m trying to learn more about 3D design, but I’m definitely a n00b. I realize that it’s difficult to work just from an STL file, but even when I’ve tried other 3D design programs to import it into an editable shape, the “push/pull” tools are ineffective.

Z84_Canopy.stl (646.5 KB)


STL files do not contain the original reference geometry to reconstruct the solid and will at the very best result in an approximation.
What happens is the resulting surfaces have many control points (both along and across) that are exponetially more complex and degraded. |As a number of these poorly defined surfaces are used to construct your model process gets time consuming, inaccurate and unstable. This is true if the conversion is repeated numerous times during the model creation. Once you have imported the model into SU use a tool like Thomhom’s cleanup tool ( You will have to download that from the 3d ware house and install on your machine… Once I did that it looks like you could save out the portion you want to work on, save it as component , the make your mods. Making it a component off to the side will isolate its geometry from the rest of model and make changes easier. You may the have some other issues to make it solid assuming you want to print it but one stepcanacopy.skp (1.4 MB)
at a time.


did you try to open the attached skp file? If you cannot open that it probably means you have older version of SU. Let us know what version you are using we can save it for you in older versions.
Update you profile and include also the version of SU have.
Here is case of selecting the front rectangle and just scale it down slightly, there will be some auto folds you will have to hide . Done without making it a component. canacopyA.skp (1.3 MB)
Saved in Su2016 for you in case that is needed.


Thanks so much, max7595! I just got home and tried the skp file. The first one you posted, I think, will do the trick. I used the P/P tool plus ctrl, and moved the face I wanted to move up to where I wanted it. I then erased the original face. What I need to figure out now is how to cut away the extra “walls” that were flush with the original face at the edges, so I’ve got some more amateurish blundering around to do tonight. :wink:

How did you convert the stl file to an skp file, if I may ask?