Set transparency on material with node

Here’s an example for you it may be. You can shange Value using Puzzles to switch on\off transperecy of the object.

marshallus wrote:

Is-it possible to control opacity (like 0.5 for example)

Yes, but you need to set it to Alpha Blend type of the transperency instead of Alpha CLip.

Hi
You might want to use translucency.
For either translucency or transparency use a png file with a transparent background, in an image texture.

Start with a texture coordinates node (uv or object) to a mapping node to the image texture to the Fac of a mix texture node. Top input of the mix transparent or translucent then bottom one diffuse or emission… Then out to material output.

To control the amount of transparent then put an RGB into the transparent color socket then you can change its color and alpha