Hi, I have a question I can't achieve the background blur like in the attached video in Vegaspro21 but in VegasPro18 yes. I can they changed the masks somehow? I have been using this method for a long time. Something is different ? 
Masking has changed a lot since the method shown in Vegas Pro 14, the tutorial that you've linked in your post.
To learn about masking in Vegas Pro 21, refer to the user manual in Vegas Pro 21 (via the Help menu) as well as watch a couple of YT tutorials about masking in Vegas Pro 21:
and
You'll likely find other Vegas Pro 21 masking tutorials with a YT search.
BTW, you've posted on the forum using the Vegas Effects category.. Vegas Effects is not Vegas Pro but an additional program that comes with the POST version of Vegas Pro.
I can't achieve
This is a very broad description. You need to describe it in detail.
That technique works fine for me in Vegas 21 ...
i know it's vegas 14, but this method worked for me in vegas 18pro too, i know they are smart mask, but i struggle a bit with them in terms of accuracy, but that's my inexperience, so i needed it manually.
Yes, I know, I misclicked on the category.
And specifically these tutorials, I saw. I just didn't realize that it changed what I needed.
@Dexcon
Just a small side note re the careless branding of the v. 14 tutorial by its creator. It was VEGAS Pro 14 as shown in the actual video. The last Sony versions were #13.
The thread has been moved.
I will improve the description, unfortunately I don't have a project with me But only a photo from my mobile.
I have two people in the room and I want to use a mask to blur the background behind them. I like to use the method in the video above. Now it is definitely better, to use a smart mask, But I was not happy with my result. ( because with the smart mask I am still learning)
