# Contours have "cracks" at zones boundaries (partially solved)

**URL:** https://discourse.paraview.org/t/contours-have-cracks-at-zones-boundaries-partially-solved/4290
**Category:** ParaView Support
**Tags:** vtk
**Created:** [May 8, 2020, 4:59pm UTC](https://discourse.paraview.org/t/contours-have-cracks-at-zones-boundaries-partially-solved/4290 "2020-05-08T16:59:16Z")
**Posts on this page:** 1
**Page:** 1

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### Author: ![liangwang0734](https://discourse.paraview.org/letter_avatar_proxy/v4/letter/l/3ab097/32.png) [@liangwang0734](https://discourse.paraview.org/u/liangwang0734)
#### Post date: [May 8, 2020, 4:59pm UTC](https://discourse.paraview.org/t/contours-have-cracks-at-zones-boundaries-partially-solved/4290/1 "2020-05-08T16:59:16Z")

</div>

I have an unstructured mesh Hexahedron data (I have attached a slice of the grid).

When I make contours in ParaView there are “cracks” at zones boundaries. Visit looks OK.

Any idea how this could be improved?

Edit 1 5/8 13:09:  
It turns out the problem only shows up if I use different opacities for many (\>5) different contours. Each contour surface is OK. But Paraview might be smartly taking into account the local grid shape, but somehow this creates the “cracks”.

Edit 5/8 13:15:  
The cracks seem to be overlapping effects of different layers. So supposedly visit will have the same effects, but I don’t know to apply opacity to contour colormaps for predefined colormaps.

Edit 5/8 13:27:  
I haven’t “solved” the problem. But after selecting fewer contour values the “cracks” are not very apparent, which is an acceptable result for me.

 ![grid-slice](https://discourse.paraview.org/uploads/default/original/2X/2/2c566fd2d80841a75a0f5100a2d6573611983912.png) ![paraview0000](https://discourse.paraview.org/uploads/default/original/2X/e/e871de2ee67e927a0f1106213e2cd0c32f1d9966.png) ![visit0000](https://discourse.paraview.org/uploads/default/original/2X/e/e7f845246ae6e8644d980c64872022e989238225.jpeg)