# NanColor retro-compatibility needed or not

**URL:** https://discourse.paraview.org/t/nancolor-retro-compatibility-needed-or-not/201
**Category:** Development
**Tags:** backwards-compat
**Created:** [June 18, 2018, 2:20pm UTC](https://discourse.paraview.org/t/nancolor-retro-compatibility-needed-or-not/201 "2018-06-18T14:20:24Z")
**Posts on this page:** 2
**Page:** 1

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### Author: ![mwestphal](https://discourse.paraview.org/user_avatar/discourse.paraview.org/mwestphal/32/17_2.png) [@mwestphal](https://discourse.paraview.org/u/mwestphal)
#### Post date: [June 18, 2018, 2:20pm UTC](https://discourse.paraview.org/t/nancolor-retro-compatibility-needed-or-not/201/1 "2018-06-18T14:20:25Z")

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We are in the process of adding support for NanColor opacity in ParaView.

There is already support for it in the Color Selector, wich shows a opacity widget when the associated property as 4 components.  
However, increasing the number of components on NanColor property would break retrocompatibility with older .pvsm as well as with code manually setting the property.

We could instead add a new property NanOpacity, with it’s dedicated slider.

What do you think ?

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### Author: ![cory.quammen](https://discourse.paraview.org/user_avatar/discourse.paraview.org/cory.quammen/32/11193_2.png) [@cory.quammen](https://discourse.paraview.org/u/cory.quammen)
#### Post date: [June 18, 2018, 2:47pm UTC](https://discourse.paraview.org/t/nancolor-retro-compatibility-needed-or-not/201/2 "2018-06-18T14:47:43Z")

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I think a separate opacity property would be preferable, and is consistent with the separation of solid surface coloring and opacity in the Geometry Representation.