Does Face Orientation Matter

[adameee]

If I will be neither rendering nor 3d printing a particular file, does face orientation matter? I am spending too much time reversing faces. Can I not just set front and back faces to the same color and forget about it?

[whiterabbitdesigncompany]

I guess you could, however, there are also some plugins that function based on face orientation so they may not work as expected? Have you tried the right click - orient faces -? that’s a quick way of getting them all going the right way. There’s also an extension - left click reverse tool - that makes this task easier too. Not sure why you would be getting so many reversed faces to begin with?

I’d say it’s a better habit to get into drawing with the correct orientation so that possibly one day down the line when you may need to render or 3D print, that you will be used to having everything correct.

[g.h.hubers]

@adameee

I am spending too much time reversing faces.

You can also create a shortcut key for ‘Reverse Faces’.
Now when hovering over individual faces with say the ‘Push/Pull’ tool (they get highlighted) you can just hit that shortcut key to reverse them. Fast!

[Forestr]

You got it. Face orientation doesn’t matter when you’re not rendering or 3D printing. If you want to render, you can orient faces after the model is done. I think the easiest way to orient faces is with solid inspector².

[DaveR]

As wrdc said, there are some tools that are affected by face orientation. Even if you aren’t rendering or 3D printing your models, it’s best to stay on top of making sure faces are correctly oriented as you go. It can save you problems later and it’s just sloppy modeling to leave reversed faces.

@adameee

I am spending too much time reversing faces.

It may be that you could revise your workflow to reduce that. I don’t seem to have a lot of issues with reversed faces. Perhaps the most likely time I’ll get it is after Follow Me.

[DaveR]

Somehow you misread that because that’s not what I wrote. Sometimes after Follow Me the resulting faces will be reversed. Face orientation with the results of Follow Me depends on the direction of the path and the face orientation of the profile but it’s not worth chasing it. If the faces are reversed after running Follow Me, I select them all and correct the orientation.

If I ever download a component from the 3D Warehouse and find loads of reversed faces, I won’t even bother to fix it. I either look for another one or I draw the thing myself. If the author has been sloppy on face orientation, there are likely other problems that need to be fixed, too.

[g.h.hubers]

Not being bothered by reversed faces is like driving on the wrong side of the road since there’s no other trafic.

[DaveR]

@Forestr

But which extensions (aside from rendering extensions) are affected by reversed faces?

You seem to have a difficult time with reading what I’ve written. I never mentioned extensions.

Push/Pull is one that is affected by face orientation when, for example, you double click on faces.

(my template’s back color is set to green.)

[DaveR]

Either way, leaving reversed faces is sloppy work.

[g.h.hubers]

@Forestr

… you can orient your faces later, but you can’t change your traffic violation later.

In that case you should reverse your ticket.

[DaveR]

I was agreeing with him that face orientation can be important.

[g.h.hubers]

@Forestr

Which tools (aside from rendering extensions & 3D print extensions) need oriented faces to function?

‘Push/Pull’ might, as shown by @DaveR.
Also ‘SolidTools’ might give incorrect results (faces missing) or you may get wrong volumes with multiple shapes with mixed front/back faces.

[DaveR]

@Forestr

It’s really not that big of a setback though because you can quickly undo the incorrect push/pull, then push/pull it the correct direction.

Sounds like work harder, not smarter to me.

[Speaker]

I can see a few problems with reversed faces:

• More difficult to apply materials to multiple faces;
• Can introduce errors with area calculations - where you can accidentally select the wrong faces;
• In some styles the face direction really matters;
• You wont be able to make a proper poche section cut in SU version before 2018;

To clean models really fast I use 3 shortcuts

• Shift + A = Solid Inspector;
• Shift + S = Merge faces (CleanUp);
• Shift + D = Erase stray edges (CleanUp).

I always try to do this with architectural models, so that I know there will not be any problems when using Solid Tools, applying different styles, making area calculations or section cuts.

[IanT]

@Forestr

It’s really not that big of a setback though because you can quickly undo the incorrect push/pull, then push/pull it in the correct direction.

@Forestr

Push/Pull still functions with reversed faces, but

@Forestr

I think it’s less work to redo misdirected push/pulls throughout the modeling process, than to orient the faces throughout the modeling process.

Forestr, the way that is and has been talked about as correct concerning reverse face on this forum, is to correct them as you go. It’s a sure fire way to lay the path as you go ensuring the fewest problems down the line. You’re coming up with excuses left right and center as to ignore them. In many cases it will lead to further problems, that’s the long and short of it.

No educated regular on this forum is going to say “yeah you should be ok just leave it, sounds like it’ll be fine”. They’ve probably ignored face orientation in the past and been punished by it, fixed it for a few hours, sat back and thought, “I’m never doing that again, I must tell the others”. They are telling you for good reasons.

Apart from the problems mentioned already, there’s the 3d Warehouse too. You upload your reversed face model there and some poor sod makes the decision to 3d print or render it etc,etc. Depending on how bad it is they might as well have just drawn the thing themselves by the time they’ve finished. You didn’t have any problems, but down the line they did.

[IanT]

Still, I’m not going to say it doesn’t matter for this case either. I’m talking about the ethic of SketchUp as a whole, whether it convinces you or not.

[DaveR]

Sloppy modeling often does come back to bite the author by making them work harder. Since it’s easy enough to make clean models, there’s no excuse for not doing it.

[IanT]

Try to cheat all you like, I’m out of the thread. There’s no point in trying to convince you, sorry.

[Box]

I can’t think of many things worse than having back and front faces the same colour. How do you know when you are looking inside something, how do you spot holes, when you apply a material it will randomly cover sections depending on their true orientation.

Not knowing how a face will work with a double click as already mentioned is not something to ignore, undo and push the other way will get very confusing.

It will certain affect extensions that rely on face normals and you wont be able to see why it’s going wrong. SUbD, WrapR, Clothworks, Artisan just to name a few.

These are just a few of the reasons for keeping on top of face orientation.
There is no good reason for ignoring face orientation, even laziness because you will end up working harder in the end.

[Forestr]

Texturing geometry with reversed faces is easy if you make it a group first. I have the group command as a shortcut, so it’s really fast.

You can use inferencing to extrude reversed faces to the same height. It takes the same amount of clicks as double clicking.

Artisan’s subdivide tool can handle reversed faces just fine.