Double nods to Phil B. and Zhaph - Ben Duguid ♦ for offering correct answers, but Mark Thrill has provided further detail that might be a program issue, or he might have just said these words in jest.
"I've been looking for it for hours on LDD..."
We know that certain versions of LDD do exclude pieces. The version of LDD that I'm using does have both variations of this piece. So, Mr. Thrill, if possible can you check again to see if your version has these pieces:
If you just type "1x4x1" in LDD's search field, both variants should pop up underneath the subcategory brick image that's often used for a car's headlight.
Also could you please tell us what version of LDD you're using.
Help Menu> About (F3).
I'm using 4.3.11 in Extended Mode.
It might be nothing. I know sometimes a piece's orientation gets rotated weird in the side tab of the program, and the piece we're looking for is right there in front of our eyes, but the inner mind's eye hasn't caught up yet.
So, both variants in LDD would be:
- (Thicc) Part #52038 1x4x1 2/3 W. V. KNOBS.
- (Thin) Part #14520 1x4x1 2/3 W. V. KNOBS.