Did that occur because you still had the affected faces selected in edit mode–Blender thus casting the orange selection color over the gray metal color?
Give everyone a clue!
What occurred? When?
General Q&A note
Help us all to help you.
Please give full screenshots with any questions. With the relevant panels open.
Also, include the lecture time and name/number that is relevant to the problem/issue.
The screenshot can be done by Blender itself, via the ‘Window’ menu bar top left hand side.
On that menu drop down is ‘save screenshot’.
Close ups additionally where they help.
1 Like
This, what Nicholas said. I was thinking the same thing. @ exactly 6.00 minutes into the video. No biggie 
1 Like
Ah right, TY.
No, it is a glitch. Grant would know if it was some error a user could make somehow and use it as a teaching opportunity. He was probably making it in a Blender version not yet official, to help keep things up to date by the time it is finished. So some glitches do crop up, letting people use the unfinished next versions helps Blender as these things get reported and sorted before the official releases.
3 Likes