Hi, I was wondering if I could get some advice with shadow settings. When i turn “use sun for shading on” I seem to loose the textures of materials and the colour go weird, however when i turn it off the textures and colours look better but it is too dark. Any advice?
Set the Light slider more to the right and the Dark slider more to the left.
ok, some basis of light in sketchup.
by default, you, the user, are the light source. that’s what you see on your second image, the faces facing you are lit, the ones not facing you are not lit.
In the shadow panel, if you click on the cube (top left), it’ll activate the shadows. then with the cursors you can adjust time and date, and contrast.
When using the shadows, you are not the light source anymore. there is a sun.
if you turn off the shadows, BUT you tick the “use sun for shading”, it’s a mix : you don’t have the drop shadows like before, but also you’re not the light source anymore. SU will use the sun as a light source
then why is your first image so dull ? Because you’re inside. there is no sun inside. and to have a “not too dark” image you had to push the “dark” cursor right.
what to do ?
Besides the obvious rendering tool, I’m sure someone will come around to talk to you about vray and esncape - the evangelists aren’t very far - there are tricks you could do.
One, obvious, is to use the standard light, where you are the lightsource.
The main trick is to paint the outside of your walls / ceiling transparent : every face has a recto and a verso. it’s the basic idea behind a see-through mirror. stupid idea, better one next post
Thanks for your reply I don’t know what you mean by this? Do you mean painting them in a glass texture?
forget what I said, I had something else in mind, and I gave you a wrong direction to go dig.
the eye to mask it
the lock to lock it (duh…)
and two cubes.
if you click on the first one, the objects you’re selecting won’t get shadow on them.
the second one is the one you need. it’ll tell sketchup that the objects selected won’t cast shadow.
I select the ceiling group, click on the 4th cube and now :
here, I’m lazy, I"ll just select the whole wall group and click on the third cube, so no shadows are visible on the wall. it’s a trick. sometimes it’ll hold, sometimes it wont.
off course, this is fake, it’s smoke and mirrors, just to have some contrast and shadows in the image. it’s like removing a wall and the ceiling of your physical model. so it’ll require trickery from you aswell.
If you want to go further, you’ll need to start reading about rendering softwares, they’ll allow you to work with ambiant light (not just a mega sun-spotlight like here), artificial light, ambiant occlusion… it’s a rabbit hole 
