Distortion in area adjacent areas after scale tool use?


#1

I have used the select & scale tool to reduce part of building by 97.5 fraction, ie about 200mm off a 8350mm side using a middle grip. Parts of building beyond area reduced, drawn on another level were switched off. If I want to draw on these areas now a simple rectangle always ‘fills’ as triangular shape / series of triangles as if some unseen distortion has occurred. If I want to push / pull separate triangles form. They all extrude as if they are from a common level base, ie push / pull in same axis. Anyone had a similar experience? Have tried erasing and redrawing but rectangle always reverts to triangulated shapes. Will try to add a screenshot to illustrate problem.


#2

It would help if you can post your actual model rather than a screenshot (though uplinked files are currently broken on the forum…). However, on the surface it sounds like you are making a very common mistake: in SketchUp layers do not isolate geometry from interaction with other geometry, layers only allow you to make items selectively visible or hidden. To isolate geometry, you must put it into a different Group or Component.


#3

It’s clear you’ve run afoul of SketchUp’s layer system.
Layers in SketchUp do not isolate geometry, thereby protecting it from unintentional alteration.

Layers in SU control visibility, nothing more.
And visible or not, unprotected geometry interacts with other unprotected geometry.

Making logical portions of the model into Groups and Components isolates the geometry within them.

Required Reading:
Does SketchUp Support Layers? — SketchUp Help

Groups and Components


Layers


#4

Thanks for reply. I haven’t many hours practice so expect it is common
mistake. I understand the group and component aspect.
What I can’t understand is why the erasing of all the lines​ / previous
geometry doesn’t clear the sheet / area as when I redraw over
it the triangles reform & connect to previous points despite them being
invisible. Thanks again for your insight.


#5

Possible explanations…

A stange and subtle fact is that although hidden geometry interacts with visible geometry as you draw, you can’t select hidden geometry to, for example, erase it! To be able to select and edit hidden geometry, you must unhide it (Edit->Unhide->All) or make it visible (View->Hidden Geometry). Or if you made the other common novice mistake of drawing primitive edges and faces on a layer other than layer0, make the other layer visible, reassign the geometry to layer0 using the Entity Info window, and then erase.

If vertices are ever so slightly askew in your model (usually as a result of not using the inference system carefully), surfaces that look planar may actually be non-planar and will form triangles instead of rectangles. Very tiny errors, too small to see without enormous zoom, will cause this.


#6

Again thanks for reply & help with selected video. (I am familiar with Autocad & Microstation layer system.)


#7

Clearing the hidden geometry from model solved my problem of drawing over the ‘distorted’, ‘blank’ area.
I encountered the last problem that you described after tracing over a pdf copy of autocad drawing and thought the same small errors were causing ‘triangulation’ here. All the triangles filled up with ‘paint bucket’ finishes separately but rendered as if all one.
Thanks again. ( I did look through previous posts to see if any similar problems were listed. If you want to re title this post to make it useful, searchable for others, be my guest.)