It’s simple. When paying for the add-on, you are not paying for the add-on you are buying. This add-on is already written. The developer has already spent his time and strength on it. About this particular add-on – there is completely no difference will it be paid or not. So, why to pay? You pay for the future. You pay for the add-ons that the developer writes now and will write in the future. If the addon is bought, the developer has the opportunity to continue development. If not, he will do something else, and you will not receive new add-ons, as well as enhancement and porting to future platforms existed. When paying for an add-on, you provide, first of all – for yourself, the opportunity to receive new add-ons and technical support for the old ones. Pay for add-ons and donate for free – this will benefit yourself!
Due to the nodes structure changes in the latest Blender 2.81 release, all open materials in the BIS library have been updated for this version of Blender. Compatibility with younger versions of Blender could be lost (depends on the nodes used in the material).
Button click in basically connected with the operator calling in Blender user interface. However, some times actions, that need to be performed when a button is pressed, are quite simple and do not require a separate operator for them. And it makes no sense to fill a registered operators stack with a multitude of specific operators designed to perform one highly specialized function. It would be much more convenient to associate a button press with a separate function call but the Blender API allows to associate buttons only with an operator call.
To solve the problem of creating a separate operator for each button we can use the fact that the operator can be called with the input parameters.
When we create a field on the add-on interface panel, the value of which changes something in the node tree, each time the user changes the field value the node tree recompiles. If the user changes the value in that field by holding and moving the mouse, too frequent node tree recompilation will cause Blender to hangs.
This problem can be solved using decorators for deferred updating of the node tree.