Shading isometric pixel art
There is no rule for shading isometric pixel art. It's an aesthetic design decision which depends on the vibe you want your artwork to have.
Even though pixel art is often highly stylized and mostly doesn't involve realistic lighting, adding shading is an emulation of a light source. It can be helpful to be aware of some of the ...
Lots of pixel art doesn't 'calculate' any shading or other lighting colours, for they use a fixed palette. Just find the most appropriate colour (or the least unappropriate, in some cases) in the palette you're using and go with that.
This palette limitation is to emphasise pixel art's simplicity and it harkens back to the old computer systems the medium ...
For those who are still wondering, here's an Isometric Grid Template I made with the grid overlaying an artwork layer.
You are free to download and use as desired.
I made a bunch of triangles laid out, then applied a thin dashed stroke at a lower opacity on a locked layer above the artwork.
Well, there is a formula (or many formulations) but that depends on what material you have and what direction your light is shining from, the formula uses stuff like Sin and Cross product.
However, nobody uses this, because they can just choose colors by themselves. After all if you are manually drawing the isometrics its mostly about taste.
OTOH, if you ...
For line extension to work on a rotated rectangle, it must still be designated as “Rectangle” in the layers panel.
Rectangles become Paths if you skew them, or unite them with another object. In that case, add a Rectangle, rotate it to the same angle, and centre the two. The line extension will use the Rectangle for the constrain angle.
An ellipse will ...