# Need help with UVewa undistort\>redistort flow **URL:** \ **Category:** Flame Questions\ **Tags:** uv\ **Created:** [November 14, 2024, 7:14pm UTC](https://forum.logik.tv/t/need-help-with-uvewa-undistort-redistort-flow/11747 "2024-11-14T19:14:05Z")\ **Posts on this page:** 6\ **Page:** 1
**Author:** ![c64](https://sea2.discourse-cdn.com/flex020/user_avatar/forum.logik.tv/c64/32/2457_2.png) [@c64](https://forum.logik.tv/u/c64)\ **Post date:** [November 14, 2024, 7:14pm UTC](https://forum.logik.tv/t/need-help-with-uvewa-undistort-redistort-flow/11747/1 "2024-11-14T19:14:05Z")
Have I set this up correctly? When I difference matte, the source and result match perfectly in the centre of the shot, but there is an area around the edge that is missing in the result (black area in screenshot). What am I missing here? ![Screenshot 2024-11-14 at 8.03.31 PM](https://us1.discourse-cdn.com/flex020/uploads/thedepartmentofexternalservices/original/2X/3/3892c4e5794f145cb1e60c54f1eb7b6cec9f1fe0.jpeg) ![Screenshot 2024-11-14 at 8.12.39 PM](https://us1.discourse-cdn.com/flex020/uploads/thedepartmentofexternalservices/original/2X/a/abb157d03f9d73af46072918799a6ca3222ea8fa.jpeg) ---
**Author:** ![finnjaeger](https://avatars.discourse-cdn.com/v4/letter/f/e99b99/32.png) [@finnjaeger](https://forum.logik.tv/u/finnjaeger)\ **Post date:** [November 14, 2024, 7:35pm UTC](https://forum.logik.tv/t/need-help-with-uvewa-undistort-redistort-flow/11747/2 "2024-11-14T19:35:48Z")
any reason why you arent using the native new lensdistort/stmap nodes? Its quiet funny that there are so many different ways of how to do distortion and overscan handeling, this looks like the resolution on the distort and redistort STmaps are flipped. Undistort should make the plate larger (if thats the kind of distortion, i guess it is) in your case however - its same resolution as the plate, so my guess is that after the first uvewa node you are cutting off pixels that you cant get back, the stmap should be larger, does it maybe have a larger data window? havent used the UWewa nodes in a bit but how does it derive that undistorted resolution without a stmap of that size? If you send me 1 frame and the STmaps i am happy to have a look 🙂 ---
**Author:** ![c64](https://sea2.discourse-cdn.com/flex020/user_avatar/forum.logik.tv/c64/32/2457_2.png) [@c64](https://forum.logik.tv/u/c64)\ **Post date:** [November 14, 2024, 7:38pm UTC](https://forum.logik.tv/t/need-help-with-uvewa-undistort-redistort-flow/11747/3 "2024-11-14T19:38:20Z")
Thanks Finn! I’ll PM you ---
**Author:** ![finnjaeger](https://avatars.discourse-cdn.com/v4/letter/f/e99b99/32.png) [@finnjaeger](https://forum.logik.tv/u/finnjaeger)\ **Post date:** [November 14, 2024, 7:51pm UTC](https://forum.logik.tv/t/need-help-with-uvewa-undistort-redistort-flow/11747/4 "2024-11-14T19:51:53Z")
example here of it working, checking your pn in a hot second as well ! step by step screenshots. ![image](https://us1.discourse-cdn.com/flex020/uploads/thedepartmentofexternalservices/original/2X/c/c9bb752132e86f461bc87e0e8e3674a6b0e5ebab.jpeg) ![image](https://us1.discourse-cdn.com/flex020/uploads/thedepartmentofexternalservices/original/2X/f/f6518d6537f480b0ce446363ad76274ae368c81b.jpeg) ---
**Author:** ![cnoellert](https://sea2.discourse-cdn.com/flex020/user_avatar/forum.logik.tv/cnoellert/32/559_2.png) [@cnoellert](https://forum.logik.tv/u/cnoellert)\ **Post date:** [November 14, 2024, 7:54pm UTC](https://forum.logik.tv/t/need-help-with-uvewa-undistort-redistort-flow/11747/5 "2024-11-14T19:54:30Z")
> [@c64](#): > > Have I set this up correctly? When I difference matte, the source and result match perfectly in the centre of the shot, but there is an area around the edge that is missing in the result (black area in screenshot). What am I missing here? The stmap node makes a lot of these headaches go away. If you don’t have it for some reason though… > [@ST Maps for undistort](https://forum.logik.tv/t/st-maps-for-undistort/1664/29): > > @johnt, here you go. I also simplified it even further… ---
**Author:** ![c64](https://sea2.discourse-cdn.com/flex020/user_avatar/forum.logik.tv/c64/32/2457_2.png) [@c64](https://forum.logik.tv/u/c64)\ **Post date:** [November 14, 2024, 8:08pm UTC](https://forum.logik.tv/t/need-help-with-uvewa-undistort-redistort-flow/11747/6 "2024-11-14T20:08:42Z")
Thanks for the STmap node clues! I had the distort plates the wrong way around due to me being confused by their labelling - dang! Thanks everyone for the quick help 🙂