# The crack inside the cylinder **URL:** \ **Category:** 3DEC\ **Created:** [May 4, 2022, 6:08am UTC](https://forum.itascainternational.com/t/the-crack-inside-the-cylinder/493 "2022-05-04T06:08:03Z")\ **Posts on this page:** 7\ **Page:** 1
**Author:** ![Ray](https://avatars.discourse-cdn.com/v4/letter/r/e9a140/32.png) [@Ray](https://forum.itascainternational.com/u/Ray)\ **Post date:** [May 4, 2022, 6:08am UTC](https://forum.itascainternational.com/t/the-crack-inside-the-cylinder/493/1 "2022-05-04T06:08:03Z")
When I was doing the UC test in 3DEC, I opened the cutting tool. Then there were some line like cracks inside the block. Although I turned off the zone factor, it still there. I would like to know what is this. ![image](https://canada1.discourse-cdn.com/flex031/uploads/itasca/original/1X/0c2f5808b14796356b15734feb6573170f381c38.png) ![image](https://canada1.discourse-cdn.com/flex031/uploads/itasca/original/1X/46b08d4610166accea85c0ca4eff1d8a960dde3a.png) ![image](https://canada1.discourse-cdn.com/flex031/uploads/itasca/original/1X/3934e356f8159ef71e0c447052df17a1ef818095.png) [0504-1336.dat](https://forum.itascainternational.com/uploads/short-url/7q8sVKS2Ap0tXo893Mo6YEmsZEg.dat) (2.0 KB) ---
**Author:** ![markus](https://yyz1.discourse-cdn.com/flex031/user_avatar/forum.itascainternational.com/markus/32/288_2.png) [@markus](https://forum.itascainternational.com/u/markus)\ **Post date:** [May 4, 2022, 7:51am UTC](https://forum.itascainternational.com/t/the-crack-inside-the-cylinder/493/2 "2022-05-04T07:51:50Z")
Edit: Forget my answer, I misunderstood your question 🙄. Jim has you covered below. ---
**Author:** ![jhazzard](https://avatars.discourse-cdn.com/v4/letter/j/4af34b/32.png) [@jhazzard](https://forum.itascainternational.com/u/jhazzard)\ **Post date:** [May 4, 2022, 2:41pm UTC](https://forum.itascainternational.com/t/the-crack-inside-the-cylinder/493/3 "2022-05-04T14:41:16Z")
I think the question is about the lines crossing the blocks in the cutplane view. This is just a plotting artifact. You can move the cutting plane forward or backward slightly and they might go away. It looks a bit weird, but it’s nothing to worry about in terms of your calculations. ---
**Author:** ![Ray](https://avatars.discourse-cdn.com/v4/letter/r/e9a140/32.png) [@Ray](https://forum.itascainternational.com/u/Ray)\ **Post date:** [May 5, 2022, 1:57am UTC](https://forum.itascainternational.com/t/the-crack-inside-the-cylinder/493/4 "2022-05-05T01:57:18Z")
OK, thank you so much. ---
**Author:** ![uncleyuan](https://avatars.discourse-cdn.com/v4/letter/u/f17d59/32.png) [@uncleyuan](https://forum.itascainternational.com/u/uncleyuan)\ **Post date:** [May 12, 2022, 6:53pm UTC](https://forum.itascainternational.com/t/the-crack-inside-the-cylinder/493/5 "2022-05-12T18:53:55Z")
dear ray， I saw there are hexahedral blocks or zones in your model, are they deformable or rigid? how to generate hexahedral zones in 3dec？thanks in advance. ---
**Author:** ![RockEugieK](https://yyz1.discourse-cdn.com/flex031/user_avatar/forum.itascainternational.com/rockeugiek/32/212_2.png) [@RockEugieK](https://forum.itascainternational.com/u/RockEugieK)\ **Post date:** [May 25, 2022, 8:13am UTC](https://forum.itascainternational.com/t/the-crack-inside-the-cylinder/493/6 "2022-05-25T08:13:54Z")
@uncleyuan you can start by creating a rigid block with commands like **block create brick** **(X1,X2 Y1,Y2 Z1,Z2)** **block densify segments X Y Z hexahedra** ---
**Author:** ![uncleyuan](https://avatars.discourse-cdn.com/v4/letter/u/f17d59/32.png) [@uncleyuan](https://forum.itascainternational.com/u/uncleyuan)\ **Post date:** [May 26, 2022, 1:55pm UTC](https://forum.itascainternational.com/t/the-crack-inside-the-cylinder/493/7 "2022-05-26T13:55:38Z")
thanks, are these rigid blocks which were used in the above example?