# Need help trying to project shape onto cylinder…

I'm trying to take this cylinder and circle combined shape and remove it from the pyramid so the pyramid has a hollowed out shape. Tried to do it with boolean difference, which didn't work and now I've tried knife project. Which also doesn't work. For some reason the cylinder shape doesnt seem to be registering as a usable object?

• Not sure how to do this, but Knife Project didn't work because the object acting as the knife must have no faces, for an example, create a plane, select the plane in edit mode then press <kbd>X</kbd> and then remove only faces. That should allow the knife project to work. – Luka ash May 10 '16 at 20:57
• Welcome to Blender.SE! I'm not sure to get exactly what you would like to do: project a shape or booleand difference between two solids?Are both object watertight meshes? Maybe you can upload your blendfile to blend-exchange.giantcowfilms.com so it can be inspected. – Carlo May 10 '16 at 21:26
• Possible duplicate of Why doesn't the boolean modifier work for me? – someonewithpc May 10 '16 at 21:59
• Hi guys - Thanks so much for your help. I'm obviously a complete noob here. What I'm trying to do is to remove the cone/sphere object (which is two objects joined together) from the pyramid. (So there will be a hole shaped like the joined object in the pyramid). I tried removing the faces, and the knife projection worked however what resulted was just a glitchy mess, with no actual indent in the pyramid. – Lily Streeter May 10 '16 at 22:47

I somewhat remade your scene, and was successful so I will contribute what I did. I think what may be causing you the biggest problem is the lack of geometry in your pyramid object. Try adding several loop cuts to support the boolean operation.

Here is what I did:

• Default cube, enter edit mode select top face and scale to 0 and scale as needed to create the pyramid object. (I also scaled the bottom face slightly).

• Add several loop cuts in each direction with Ctrl+R

• In object mode, add a uv sphere, then go back into edit mode and enable proportional editing by pressing O and select only the top vertex.

• Move the vertex on the z axis until you have the desired shape, and then scale to size.

• Go into object mode and align the sphere object with the pryamid object, and add a Boolean> Difference to the pryamid object, setting it's target to the sphere and delete the sphere from the scene or move to another layer.

After following these steps, also an edge split and subsurf modifier added- this is the result: