# Is there any possibility to adding a value beside expression in driven property?

Is there any possibility to adding a value beside expression in driven property? Formulas would be only in drivers window or not?

If I need add expression like:

self.location[0]+object.location[1]


< both value dependant

A shortcut to entering driver expressions is to start with a # - so entering #frame*0.1 will create a driver expression that sets the value to 1/10th of the current frame. You can then edit drivers using the graph editor in driver mode.

Using the # prefix works for some things that are available globally, like the current frame and some math functions - sin(), log(), noise.random() etc. To get a driver to depend on a transform channel or property, whether it is it's own property or another objects, you create driver variables and use them in your expression.

To see a full list of functions available within drivers, enter bpy.app.driver_namespace.keys() into blenders python console.

You can also define your own functions and add them to the driver namespace as shown here.

• Thank you sambler, but this is not what I ask. Problem is that, if I have some expression in property I would like controll the property (animator) even the property is purple (default expresion color) but if i want to set some number it give me only expression as i show in my main question. So I would like to freely controll "expresioned" property without see the expression, only number. – MRL Mar 11 '18 at 21:40
• @mrl you can't have both, you either use a driver that calculates the value or you manually keyframe the value. Note that you can have a driver read multiple custom properties that you can manually adjust. You can also create your own function which could use a custom property except on frame 125 where it calculates from other sources. You can also enter an expression without the # prefix and it will only be calculated at that time, but you are still limited to what properties you can access. – sambler Mar 12 '18 at 4:12
• Thank you sabler. I asked because with expressions in after Effects it is possible. And I would like round the number I set. In blender I must use other options then. – MRL Mar 12 '18 at 11:12
• @sambler I appreciate your insight, I've used drivers for years and never picked up on this method of input. Awesome nugget. – Rick Riggs Mar 13 '18 at 9:32

Yes you can...

You have to have an empty driver 1st... (Via manually create later single)

Then you have to use a slightly different format, but it works...

I have a cube named 'c1' & 'c2':

I added the following line to the "z" location for 'c1' and hit enter.

3.0 + bpy.data.objects['c2'].location[2]


It worked!

• The problem with this though, is that it does not update, when you change the z position of 'C2', you have to enter back into the 'z' location property of 'C1' and hit enter to force the update. – Rick Riggs Mar 7 '18 at 19:23
• Thank you, can you please post preent creen of "You have to have an empty driver 1st... (Via manually create later single)" Because I dont understand what you mean. And the value of property will controll some animator, so i would like have only value in Z-location - nothing else. < it must be animable – MRL Mar 7 '18 at 19:43