I have spent ages trying to sort this issue: drawing simple line on a plane (coloured with JPG image) caused extra white plane to be auto created above the original. I now find that Sketchup math calcs are all started from the Origin: and working in millimetres is 300,000 away from origin: so the calc is not fine enough to identify different planes.
I got great help from Tim in technical support - thank you.
The way to solve it (I guess) is to not have one master file (that is a bit of a problem) and split the file, so that nothing gets too far from the origin.
I copied the content into a new file, saved it, reopened it, moved the content to nearer the origin, saved it, reopened it. Tried drawing the line again - and it worked fine.
As Iām recreating St Pancras Int Hotel + train shed (150m x say 500m) the file is very large, and the detail very fine. I will have to make it in 10 master files, not 1. Durn it.
The lack of decimal control bites us all.
If you know of a plug in or other work-around, let me know!
Thanks. David
OK, hereās the file before saved again in 2026: it is 12Mb
Yes, drawing close to the origin is ideal, but until we have a look most of us wonāt be able to offer suggestions. Post your file for the best chance at helpā¦ otherwise we can all guess.
Are you using Groups / Components?
What happens if you switch to perspective for the camera?
Iām not sure exacty what has been done - but the blue faces are a single plane so drawing across them is creating another plane. Iām not sure if thatās something left over from an import or from when they were drawn at 300m at a reduced precision.
If I multiply each object vertically 1000x you can see what is on the same plane or what is not
If you want to draw in this way, then I would group this whole selection of geometry before you move it 300 meteres away - you can then edit that group (which is 300m away) with full precision.
If this is the 1st part of some larger āmaster planā, then I would save this as a component and then edit the component as a file of itās own.
You can then simply reload the component from your new saved file, itās location will remain same and the modelling youāve done within it will be updated.
In Model Info/Units you have precision set to 0mm which means it will only show you dimensions to the mm with a tilde to show they arenāt exact.
Plus you have Length snapping enabled and set to 1mm which is known to cause inaccuracy.
Then if you look you can see your guides arenāt flat, if you look at specific intersections with the display precision set detailed enough you can see the z coordinates are not the same.
This file is about 1/200th of the file so far. Most of content is created flat by drawing over pictures, using r/g/b for vert/horiz etc, and reasonably precise measurements: when I want to check visually, Iāll extrude 3D as required, and place into vertical and verify everything. all adjusted for actual size, grouped where possible, duplicated and copied around. There would be several 000 components, and of little use (the maximum of exact replication is probably 9). I wanted one master file, not a thousand component files. It looks like I cant have that.
Unfortunately not, the math that sits behind SketchUp (and almost all 3d engines) means that the precision reduces the further away you move from the world origin - so you manage this by using groups/components which bundles together the precision in their own miniature bubbles of information.
Youāll run into other practical problems of creating the model in the first place if you are drawing a 150mx500m metre file directly as faces and edges without groups/components.
Thanks for looking: This looks useful: I had no idea that precision could be set. the tilde is constantly annoying. I have now found that in āWindowāModel Info. Thanks.
Length snapping?
I also had no idea that the guides are not flat/parallel. Iāve used the tape and then text to show the co-ordinates: hmm. that is interesting. However, what is shown in the text popout seems to depend on something that I canāt discern. sometimes I get XYZ co-ords (? probably from origin?) and not at the end of a line, the length of the line? Do you know where I can get a better understanding of what the XYZ is actually measuring? It is quite possible that the guides are not created from a single surface - but the differences of .0005 millimetres is very strange on the Z.
I have used Pro for about 4 years, but mostly for small parts manufacturing (N gauge = 1/160th), so never needed bigger.
Now Iām creating St Pancras and early found that if I did not model in life scale, there were major problems with appearance. Iād build (say) a large window with jambs, mullions etc and group them. But to place walls or other items with the group meant undoing the group to get the planes to attach. The whole is to printed in colour (therefore flat) and mounted on 3D printed frameworks.So flat is what I need - see attached rear of hotel on station side, floor + roof.
Whilst Good Modelling practices can be helpful, in this case the practicalities of very little being a straight duplication make the reality quite complex.
I did look at the file when Support received it. There were enough things that needed fixing that made asking about it in the forum be the most useful thing to do.
Some things to know about:
To solve the problem where corners of a face that is supposed to be flat, are not quite flat, you can use the Eneroth Flatten to Place extension. But, it flattens to the ground. That makes fixing the floating sections harder. You can get around that by selecting a bunch of the floating parts, group them, go into the group, and then use the extension.
When doing that, some faces will merge, and you would lose materials. You could reapply the materials to the faces that are now incorrect.
In some cases the internal edges on a face, that are now all at 0 Z (after using the extension), are still not merged with the face. You can see the edges are thicker, as if they are profiles. For some of those you can select them, Cut, Paste in Place, and then the edges merge ok.
I tried a few extensions to try and get past that problem, but that didnāt help.
If this is all 2d I would be using components for all those windows, dormers, etc. - even if they vary a bit you can make them unique and make small adjustments. Same goes for the downspouts, etc.
I donāt know why you would want to draw those over and over again, especially as ālooseā geometry. Seems a nightmare to me.
I would also consider using tags to isolate things - and if the window components (as an example) are drawn with a solid background you can just place them over the wall componentsā¦ they could even be 1" above the wall so you donāt get Z-fighting. You could then bring everything into LayOut for final tweaks and export to PDF for print.
As ever it is all more complicated in the detail. The 2D āflatā facade is actually then split into 4 sheets for printing (glazing at the back, internal lintel supports, then the main brickwork, then front added wall furniture). I structured this file thinking I would be able to simply duplicate and modify. In reality, it was not that straight forward. Although it all looks similar, almost every item is different. When complete, the drawings are used to create the 3D framework that the printed card is attached to. I did not know there would be a problem with Z. I still dont know how the problem arose.
At the end, the graphics are all reduced to 1/320th pushed into Layout and printed. I have just received more from Support - so I will take a look at that.
You could create the model at real world dimensions and scale the viewports in LayOut. Iāve done that for several building models. I can use the same model for N-scale or whatever other scale I want simply by scaling the viewports.
This is a simple example I did a long time ago. This would print out from the PDF correctly for N-scale.
Hereās the 3D model placed on an image from Google Earth. This was done years ago when SketchUp used Google Earth imagery.
