What's the difference between faces

Banaticus

What's the difference between one side of an object and another? What's this reverse faces thing? They both seem to take a texture just the same.

KXI System

When you get advance you'll know.
Some programs that you can export to and from SU are more picky when it comes to the face sides. Like some renders only render the front face. To make your life easier [just in case] you should get into the habit of working with the front (white) side.
Plus, it makes your models seem more polished.

Another user with more experience on the topic might post if your still a bit foggy.

~KXI

Banaticus

Is it possible to build a box that has all of its outside faces on the inside? Perhaps that's why Hammer is rejecting the things I've been building in SketchUp. Is it possible to make the faces more obvious? Like, some setting that has one side blue and one side red or something and a way to know clearly which side is which?

TIG

It's quite possible to model your entire geometry 'inside-out'.
It will have no affect on Sketchup when you add materials, BUT if you export it and render it in most other applications the materials will not be visible as the 'back-faces' are ignored and your efforts will be wasted.
So if you have the slightest chance of giving your model to others, or using its geometry exported into another application, then make sure your faces are oriented in the way you want.
Sketchup has a 'Monochrome' mode that ignores materials and shows just front/back materials on faces.
Use this to check things are oriented correctly.
To help you can adjust the material colors for the face front/back in your current Style setting - I have a trouble-shooting Style where the front faces are off-white and the back faces are bright-blue [it also colors edges by axis, shows end-pints and hidden geometry] - by having a Scene tab set that just switches to that Style [leaves other things like view/layers/etc alone] you can see problems and fix them then swap back to your previous Scene setup...
It's a good idea to check the faces' orientation before applying many materials, and then as you evolve the model...

Gaieus

Here is Twilight Render (using Kerkythea''s rendering engine in the background) and its rendering "preference" (order) for different textures is this (as far as I remember):

materials applied on front faces
(in the lack of the above) materials applied on back faces
(in the lack of the two above) materials applied to groups/components

Now you really have to be careful especially with # 1 and 2 because you may have a material applied on a face in your model to a back face visible but if there is anything on the front face "behind", you will get surprisingly unwanted results.

Here is an example (really old model with lots of mistakes I made when I had only been using SU for about half a year)
http://www.septichora.hu/karmelita/karmelita.swf

It's an interactive spherical panorama. When loaded, navigate with your left mouse button and turn around to see the (very basic and primitive) rose window on the west.

The frame of it renders black and this is because inadvertently I used a back face there and could not see it until the render was complete (and it is a huge render so I have not had the time to remake it yet).

So unless you want to use external apps, you need not care too much but once you decide, you can get in trouble both with re-using your old models and even using your new ones if you have not disciplined yourself to keep face orientation correct all the time.