Change Details

**System Information** Windows 10, nVidia GeForce GTX 1060 6GB **Blender Version** Blender 2.79b Date 2018-03-22 14:10 **Short description of error** Normally the preview for a rendered image automatically updates when you change a property on any compositor node so you can immediately see how the change affects the final composition. However, if you make the property driven by a custom property on an object in the scene, the preview no longer updates even if the property is changed via the driver. **Exact steps for others to reproduce the error** 1) Make a simple scene with a cube. Add a custom property 'prop' on the cube and set the max value to something like 1000. 2) Render the scene to get a compositor preview. 3) Go to the node editor in compositing mode, and add some kind of node in between the render layer node and the composite node. In this example I use a Blur node with the X & Y set to 2. The composite preview updates to show the final render, a slightly blurry cube. 4) Manually create a single target driver later on the 'Size' property of the Blur node. 5) Select the Blur node and open the graph editor. (There may be another bug here where sometimes the Drivers tab won't show up immediately in the properties pane and you have to select another node then reselect the Blur node a few times until it shows up...) 6) In the drivers pane, create a variable 'var' that reads from the custom property of the cube ["prop"]. Set the expression to 'var' so that the 'Size' property of the Blur node changes one-to-one with 'prop' property of the cube 7) Change 'prop' on the cube to 20. The 'Size' property on the Blur node will likewise change to 20, but the preview image won't update. (However, if you change the driver expression to a simple literal like '20' instead of 'var', the preview will update correctly)

**System Information** Windows 10, nVidia GeForce GTX 1060 6GB **Blender Version** Blender 2.79b Date 2018-03-22 14:10 **Short description of error** Normally the preview for a rendered image automatically updates when you change a property on any compositor node so you can immediately see how the change affects the final composition. However, if you make the property driven by a custom property on an object in the scene, the preview no longer updates even if the property value changes. **Exact steps for others to reproduce the error** 1) Make a simple scene with a cube. Add a custom property 'prop' on the cube and set the max value to something like 1000. 2) Render the scene to get a compositor preview. 3) Go to the node editor in compositing mode, and add some kind of node in between the render layer node and the composite node. In this example I use a Blur node with the X & Y set to 2. The composite preview updates to show the final render, a slightly blurry cube. 4) Manually create a single target driver later on the 'Size' property of the Blur node. 5) Select the Blur node and open the graph editor. (There may be another bug here where sometimes the Drivers tab won't show up immediately in the properties pane and you have to select another node then reselect the Blur node a few times until it shows up...) 6) In the drivers pane, create a variable 'var' that reads from the custom property of the cube ["prop"]. Set the expression to 'var' so that the 'Size' property of the Blur node changes one-to-one with 'prop' property of the cube 7) Change 'prop' on the cube to 20. The 'Size' property on the Blur node will likewise change to 20, but the preview image won't update. (However, if you change the driver expression to a simple literal like '20' instead of 'var', the preview will update correctly)

**System Information** Windows 10, nVidia GeForce GTX 1060 6GB **Blender Version** Blender 2.79b Date 2018-03-22 14:10 **Short description of error** Normally the preview for a rendered image automatically updates when you change a property on any compositor node so you can immediately see how the change affects the final composition. However, if you make the property driven by a custom property on an object in the scene, the preview no longer updates even if the property is changed via the drivervalue changes. **Exact steps for others to reproduce the error** 1) Make a simple scene with a cube. Add a custom property 'prop' on the cube and set the max value to something like 1000. 2) Render the scene to get a compositor preview. 3) Go to the node editor in compositing mode, and add some kind of node in between the render layer node and the composite node. In this example I use a Blur node with the X & Y set to 2. The composite preview updates to show the final render, a slightly blurry cube. 4) Manually create a single target driver later on the 'Size' property of the Blur node. 5) Select the Blur node and open the graph editor. (There may be another bug here where sometimes the Drivers tab won't show up immediately in the properties pane and you have to select another node then reselect the Blur node a few times until it shows up...) 6) In the drivers pane, create a variable 'var' that reads from the custom property of the cube ["prop"]. Set the expression to 'var' so that the 'Size' property of the Blur node changes one-to-one with 'prop' property of the cube 7) Change 'prop' on the cube to 20. The 'Size' property on the Blur node will likewise change to 20, but the preview image won't update. (However, if you change the driver expression to a simple literal like '20' instead of 'var', the preview will update correctly)