I try to create a 3d model this way:
Draw a rectangle+drag it up to a 3d-model/box. Then I try to replace the top part of the box with a sandbox grid. This in order to modify the surface. It works well graphically but I am not able to read the volume of the solid - Sketchup does not recognize it as a solid - what is wrong?
Can you attach a screenshot?
It must not be a solid if SketchUp doesn’t recognize it as such. Hard to tell exactly what’s wrong without seeing the file.
When you create the sandbox grid it is made into a group which would be separate from the box. Explode the box and the sandbox grid, select all of the geometry and make a group. Assuming there are no holes, it should be solid.
The sand-box tool makes a surface.
This will have a surface-area.
However, it will not have a volume - it has no 3d component in its geometry
Assuming that the surface presents a 3d rectangle ‘in plan’, you could get a volume by doing the following…
The surface will have four corners.
Assess the highest one - view in any of the standard side views with perspective off.
Ensure you are now editing within the same context as the surface…
Draw a vertical line from the highest ‘corner’, constrained in the vertical - z - blue axis using shift or the arrow-keys, stop that new constrained line at the lowest point of the surface.
Draw more vertical lines from the other corners and perhaps the lowest point,
Now join the ends of each of those three vertical lines with some new horizontal lines, and also draw across to the lowest surface vertex too.
You might be lucky and the new flat base and the four vertical faces with be automatically created - but if not, draw over some of their edges to force a face to be made…
You should now have a surface with a ‘base’ and a ‘skirt’.
If you exit the edit and select the newly-skirted group - under Entity Info it should now be regarded as a Solid and also display a Volume…
Click in sequence on the scenes tabs of this SU file for ideas.
Check that the topo surface is indeed without stray edges or any glitches so that the resulting box can be seen as a solid.
Box under topo.skp (31.4 KB)