Prevent geometry nodes from overlapping bump map

Question

I'm working on some condensation using geometry nodes but also trying to use a bump map for the smallest points of condensation. Generally, it looks really good; however, when looking very close, you can see the bump map through the larger droplets created by the geometry node. Is there any way to convert the geometry data into something I can use to mask off the bump map so it doesn't come through from behind the drops? If it was real condensation, the larger droplets wouldn't have small droplets behind. Again, the smallest droplets are coming from an image, not geometry, so there's no actual object collision happening. Any ideas?

UPDATE: I used the fantastic idea from Hulifier to use Dynamic Paint, but it resulted in a slight offset. It also didn't quite capture all the droplets from my geo node.

For the below image, I left the bump off and the new mask as a black color overlay so the offset can be seen better. Here is the result.

Update 2: Using a vector math node from the comments and editing the dynamic painting get's this very close to perfect. Some settings will need to be messed with for individual setup differences.

Answer 1

With Dynamic Paint, you can use your Geometry Node's geometry as a brush and your mesh as canvas to bake a texture, then you use that texture to mask the bump and roughness in the condensation material.

I don't know if you can do that with the Geometry nodes and the mesh in the same object, you may need another object to put your nodes.

Without DP texture masking:

Resulting texture from Dynamic Paint:

Mask applied, without and with the water drop:

If your render is an animation where the water drops will move, you will need to bake all frames within the desired interval, you will also need to enable dissolve and set it's time value to 1 so areas where the drops are no longer present don't remain painted.

I used the paintmap output for this result.

Your mask paint may have a little offset from your drops, I don't know the reason, but I managed to solve this by adding a little offset to the mask texture vector input:

the values you need may or may not differ.

Now, if small parts of the painting mesh are not painting, you can try to change the brush source to Volume + Proximity with a very small distance and mess with the options below:

Edit: Using the project option seems to give better results to me.

Edit 2: perfect method

Doing this, even small geometries will paint, and in the correct location.

Forget about translating the texture. Just do this:

Before baking, translate the entire brush geometry by 0.001 in every axis:

After baking, you remove the translation.

resulting texture:

The problem cause, probably:

/* a simple hack to minimize chance of ray leaks at identical ray <-> edge locations */
add_v3_fl(ray_start, 0.001f);

This code line in the dynamic_paint.c file apparently adds a little offset to raycast origins when using a mesh brush, the result is not very noticeable in large scale objects, but in small scales produces very different results from what one would expect.