Issue using sandbox to create terrain

Hey all, I’m not new to Sketchup but am new to using the Sandbox tools. I’ve been watching some videos on how to use it but need some help if somebody is able. I’m just testing some very basic grading/terrain around a house and just having a strange issue. So I make a rectangle, say 100’x100’, i click the button to create a mesh and type 5’ for instance to set my spacing, i then click a corner and move towards another corner, click again and then head to the next corner and click and then i get my mesh no problem. i then double click on the mesh and i get some weird shadowing/geometry that seems to mess with my ability to apply a material to it once i’ve used the smoove tool to actually push/pull and create some contour.

Here’s what i get when i first create the grid:
Google Photos

Here’s what i get after i double click it, this is before i’ve ever touched smoove or added material or anything:
Google Photos

So after I do some pushing and pulling, do a quick smooth on the geography and then i paint some grass on it for instance i get a splotchy terrain where not all of it painted and i can even select these unpainted splotchy pieces.

The weird thing is that i played with this a couple days ago and didn’t seem to have this problem. I must be missing something simple.

Any help would be greatly appreciated

I could only attach two pictures to the post so here’s what my painted version looks like for example:
Google Photos

Something else i just noticed is that the shapes completely move as i pan or orbit around. super strange

Looks like Z-fighting. Guess is there is a second plane in the same location as the sandbox one you are making. select it and delete. Upload your .skp file here to get a definitive answer.


Actually I just read through your workflow. No need to make the first plane geometry before using the grid tool. The grid tool makes it’s own plane so you are just making another on top of the first. Just start with the grid tool and an empty space.

Invoke the tool
Type in number for grid spacing.
click to start grid, move in one direction,
type in first distance, enter.
move in another direction
type in second distance, enter.


That was it. Thank you VERY much. I knew it was going to be something simple and stupid. Rookie mistake.


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