Arnold - Object to become transparent during animation

[cwymer]

Hi all 🙂

I am using Arnold Renderer to animate fluid flow through a pipe. I want the pipe to appear opaque and then become transparent for a few seconds to see the fluid running through it. Then I want the pipe to become opaque again.

I have tried using the Object Properties options to change 'Visibility' settings but it does not render in Arnold 😞

I have attached a image of what I mean.

Please can you recommend a method I can do this? 

[leeminardi]

Arnold does not support the visibility track. You can use a cutout (opacity) map instead and animate it.

[cwymer]

Hi Lee,

Thank you for your reply 🙂

Under the Slate Material editor I cannot see the 'Cutout' Map. I did a search for it but no results 😞 see Attached image.

Where can I find this map?

Thank you !

[leeminardi · Accepted solution]

Add a Physical Material that will be the material that fades away.

Connect an OSL:Color map to it.  You can find the map under OSL, Values

 

Keyframe its color from white (totally visible) to black (invisible).

See the comments at this thread and the file of @Anonymous  's post #4. 

[cwymer]

Thanks for your support Lee, works perfectly 😁

[leeminardi · Accepted solution]

I just became aware that to enable the visibility track when using Arnold you must assign the object an Arnold Properties modifier then enable Visibility under General Properties.  Once you do you can keyframe values for visibility as I do in this video.

You can use this method instead of the cutout map if you wish.

Lee