@dave r said:

I don't see the fading guides but I do see that your model is positioned away from the origin. I've moved it close to the origin. See if you still get that same behavior.
[attachment=3:faw7qei1]<!-- ia3 -->Untitled.skp<!-- ia3 -->[/attachment:faw7qei1]

Also make sure the 1660 graphics card is actually being used to display SketchUp. Window>Preferences>OpenGL>Grpahics Card Details.

While we're thinking about graphics cards, go to the Nvidia site and download the latest drivers for that card and install them.

By the way, I fixed some incorrect tag usage. All edges and faces should be created and remain untagged.
[attachment=2:faw7qei1]<!-- ia2 -->Screenshot - 8_31_2021 , 10_39_27 PM.png<!-- ia2 -->[/attachment:faw7qei1]

I also purged unused stuff from the model.
[attachment=1:faw7qei1]<!-- ia1 -->Screenshot - 8_31_2021 , 10_39_44 PM.png<!-- ia1 -->[/attachment:faw7qei1]

I noticed that you have Length Snapping enabled. It would be a good idea to turn that off. Having it on is a good way to induce errors into your model.

And thanks for updating your profile. That info helps us help you and it's nice to be able to just look it up when we need to know it.

Ooh, i didnt have issue with your file, no fading guideline. I will do as you did and see what happen. But i dont know about Length Snapping, plz tell me.Btw how to fix incorrect tag 😞

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