Question about the volume and area values of SOLID objects

[frog0312]

2021-06-15T15:00:00Z

Hi,

SU File below;

210610_Quantity_Calculation_P5.skp (39.6 KB)

I would like to ask a few questions about the problems related to solids that occurred during the modeling of the bridge in huge area.

I know that when modeling in sketchup, the farther away from the origin(0,0,0) you get, the more you can’t expect proper modeling due to a bug.
(The graphic displayed on the screen is sizzling or the snap is not properly captured, etc.)

I’m seeking opinions from people with the same experience with solid objects that don’t have a fixed volume value, even if they’re not far enough from the origin.

<I just copied and moved, but the volume changed in the same model>

Here are the things I’ve been experiencing:

1. The volume starts to change when a solid object is moved from an existing location to a random location about 10km. As it moves further, the volume value changes in proportion to the distance. Sometimes just copying nearby makes a difference.

2. Check changes according to modeling tools

• If you copy or move a solid object created with the line tool, arc tool, circle tool, push-pull tool, move tool, or rectangle tool, the volume changes.
• Even if a solid model is created using only the line tool, the volume changes if the position is moved more than 10 km.

3. When a solid object of the same dimensions (100x100x100 cubic) is created on multiple different desktop PCs and moved by the same distance, the volume at each desktop PC changes and the different numerical values ​​are different for each desktop PC. Even when the file is saved and reloaded, the volume changes.

4. When moving the position of a solid object in all directions of X, Y, Z axis, sometimes the volume and area values ​​in “solid volume” of Fredo6 tools do not change, but the volume values ​​in the “entity info” window of SU change.

5. If you explode a solid object whose volume or area changes when copied or moved, and make it a group or component again, the volume or area does not change any more.

Minor differences in mm are negligible because m units are used when modeling for quantity calculations.
I work in civil engineering related BIM modeling work, and sometimes I model over an area of several tens of kilometers.
If the quantity is calculated with the modeling I suggested, there will be no errors even if it is applied to the BIM process.
There is no problem to proceed with the work.
I just wonder why those values change.

The reason I am asking this question is,
When modeling with SketchUp in a huge area, I wonder if you are aware of the phenomenon that the volume and area values change arbitrarily when copied or moved even though it is the same solid object. And I wonder if there is a way to keep it from changing.

I don’t want the numbers to change under any circumstances.

[simoncbevans]

Fascinating but I don’t see the question/s.

[MikeWayzovski]

When we ordered concrete we measured in cm’s to get a rough estimate, but we always ordered 0.5 M3 extra, about 500000000 mm³.

What’s the use case?
BTW. I can’t seem to reproduce, even tried 100KM, can you share the model?

[jean_lemire_1]

I used you component at its original position and got, as you, a volume of 140 549 159 003.1 cubic mm.

I moved a copy 10 km away on thee red axis and got a volume of 140 549 159 023.669 cubic mm.

This is a difference of 1.46 x 10 to the -10 power or 0.0000000146 % which is probably OK considering the calculation precision of SU.

By the way, I would suggest that you use cubic meters for volume of such objects.

[frog0312]

Sorry. I guess it’s because I’m getting help from Ms. Google for translation.

[frog0312]

Thanks. I linked the file.

[simoncbevans]

Is that a Shakepearean quotation?

[frog0312]

I know it’s a negligible error. I would like to always display the same value for the same model.
Should I send it to the bug fixing team?

[frog0312]

Previously I accidentally pasted the wrong thing

[Anssi]

@frog0312

Should I send it to the bug fixing team?

The SketchUp team hasn’t published their recommendation for the size of the SketchUp model universe, but it is a well known “feature” of OpenGL (and the Microsoft alternative) that things go haywire when they grow big. Archicad and Revit recommend not exceeding 30 kilometers. Also, the more digits your numbers need to have, the more imprecise they become. A factor, too, might be that SketchUp stores all dimensions internally as inches, so every metric value you see has been calculated from the derived unit.

[frog0312]

Thank you for the detailed reply.
It doesn’t interfere with the work, but I want to tell my clients that “the models in SketchUp are incredibly accurate.” But I won’t be doing that for a while.