During making animations I noticed that would be nice to add new function to the Spine which could change image transparency similar to scale tool.
Now I have to put bone and put on it several images with different transparency and then switch them to obtain effect.
Transparency tool would be great and help a lot with for example smoke animations, explosions, sparks, ghost models and much more.
What do you think about it ? : )
You can set the color of the slot to change attachment transparency. You shouldn't use multiple attachments for that.
Key Frames - Spine User Guide: Slot color
The Slot Color view makes it easier.
Slot Color - Spine User Guide
It seems the user guide doesn't do a great job at making it clear that slots are used to tint attachments. I've added a little section on the images page:
Images - Spine User Guide: Tinting
Thank you for reply, I knew that I can control transparency of attachment but didnt know that I can do it several times on the time line and with just one picture. Good to know :beer:
Yep, you can set the color/transparency of the attachment itself, but that can't be animated. The slot color can be animated. 
Got it, thats what I wanted to do Thanks !
