Strange Guide Lines

Hi, I have to make a building for my school project, does anybody maybe know how I could get rid of these strange guide lines in the back? They are very anoying and I want to get rid of them, but I don’t know how.

you’re showing back edges … tap K on your keyboard

Bro thank you so much!

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You’ve also got a lot of reversed faces there, indicated by the blue-gray color on some (most) of them. You should try to model with only the white face showing on 3D volumes.

What is the difference between the white ones and the gray ones?

One is the front, one is the back. Try to keep the front faces on the outside and reverse on the inside of shapes.

Oh I get what you mean, but how is it possible to avoid that?

Generally it’s by appropriate modeling. From what little I can see in your screen shot, I’m guessing you drew the floor plan of your house on the ground plane and because the back faces is up, when you started extruding the walls, the faces were reversed.

You can avoid this by either reversing the face first or by eliminating some of the geometry like the floors before extruding the walls. There are other things that go along with that. At this stage you could reverse the faces to repair the model by either selecting the blue faces and choosing Reverse Faces or maybe right clicking on a correctly oriented face and choosing Orient Faces.

Is it a big deal? Like do I really have change it?

It depends on what you plan to do with the model. If you were going to use a rendering application to create images of it, many renderers won’t deal with the back faces. If the model is for 3D printing, it won’t print correctly with the exposed back faces. There are other things that come into play such as when applying materials. In general leaving the reversed faces is sloppy modeling and sloppy modeling means you will be working harder than you need to and future edits will be more difficult. But you can leave them if you don’t care about that stuff.

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It may affect the grade if it is a school project to be turned in.


If you context (right) click on a white face and choose “orient faces” it generally does a good job of reversing the others to match providing they are connected and in the same group.

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