This allows you to set a ground check component to require hitting a spacific actor to allow placement. For example you could use this setting on the BP_Lamp ground check component’s settings to only allow it to place on wood and stone walls, window frames and door frames.

Go to the BP_GroundCheckComponent and create a new function called HitRestrictionsCheck and add a new input called HitActor and set its type to Actor. Then add a new output called ReturnValue and set it to Boolean.

Next create a new variable called UseHitActorRestriction and set it to Boolean and tick on Instance Editable.

Next create a new variable called HitActorClassRestriction and set it to Actor Class and set it to an Array and tick on Instance Editable like the video below.

Add the highlighted nodes shown in the image below, location at the top of the image.

Add the highlighted nodes shown in the image below, location at the top of the image.

You can now select any ground check component in the build part blueprint and turn on UseHitActorRestriction then set the actor classes that ground check component must hit to allow placement. You set these classes in the HitActorClassRestriction. I recommend you only use this setting for placeables like the lamp build part for example like the image below and not grid build parts.

You can also enable the Trace Visibility in the ground check component’s settings so you are able to see where the trace is and what it is hitting if you are not getting the results you expect.