0

I am wondering if it is possible to create an object from a 'slice' from a different object which is then extruded - hard to describe. Take for example a 3d model of an open row boat with the 3d cursor in the center of the boat.

Can a 'slice' of the open row boat be taken (on the X/Y plane), duplicated and then extruded on the Z axis to form a separate object which is the shape of the open boat (on the x and Y axis) at the 3D cursor position (which is the level of the water when the boat is in the water) at any height (Z axis)?

enter image description here

enter image description here

John Arnold
  • 1,581
  • 1
  • 12
  • 26
  • You could do this with Boolean modifier e.g. – Chris Nov 19 '21 at 10:50
  • Thanks for the fast reply Chris but I know nothing about boolean modifyers and wouldn't know which one to use. You said eg but didn't give examples Oh there's only one. I will check out Youtube videos on booleans – John Arnold Nov 19 '21 at 10:54

1 Answers1

3

Yes, it is possible.

Add a Boolean modifier to a plane object set to Intersect, and intersect it with your "boat" mesh. Set the solver to a mode that works well for you (in my Susane case Fast)

After that add a Solidify modifier set to any arbitrary height, and possibly an Edge Split if you desire smooth normals or optionally tunr on Auto Smooth under mesh properties in the Properties Window.

enter image description here

This only works well if your "boat" is a manifold closed geometry without many self intersections. Some occasional artifacts are expected regardless.

You can probably get more flexible results with a new 3.0 Geometry Nodes based equivalent setup.

With the current 2.93 it is not yet possible to extrude a mesh, as far as I can tell, but you can manually add a Solidify modifier after the Geometry Nodes as a separate modifier.

enter image description here

Duarte Farrajota Ramos
  • 59,425
  • 39
  • 130
  • 187
  • any clue to do that with GN? – lemon Nov 19 '21 at 11:30
  • 1
    With current 2.93 this is what I think is possible, 3.0 probably allows an entirely node based solution – Duarte Farrajota Ramos Nov 19 '21 at 11:44
  • That is awesome Duarte and looks exactly what I am trying to achieve. Thanks heaps for that tutorial which I will try out later and then tick 'solved' I'm sure. Sorry for placing the question in the incorrect area (edit instead of modeling - I am still learning) – John Arnold Nov 19 '21 at 22:02
  • I have tried to follow your tutorial especially the animated part but cannot get my plane object with boolean modifyer to work like it does in your animation tutorial and wonder if my boat (actually a canoe) is a manifold closed geometry without many self intersections. I have added a screen shot to my initial question but cannot work out how to attach a file (a zip file containing .gltf and texture) of my canoe but have uploaded it to the cloud and avail;able here - https://mega.nz/file/K1JhCawa#tzytyxxMmOMtSTW3TrhqdnHkpFp7n0Ar1FfVoSaaKEw – John Arnold Nov 20 '21 at 02:00
  • Your canoe is not a closed mesh. Enter Edit Mode and merge by distance. See possible solutions over at https://blender.stackexchange.com/questions/50252/can-i-fill-an-empty-object/50254#50254 – Duarte Farrajota Ramos Nov 20 '21 at 02:27
  • Thanks. I applied 'merge by distance' after tearing my hair out trying to find the shortcut key(s) for Merge as most Youtube videos on the subject were created with 2.83 (press ALT + M for Merge instead of just M - so annoying) and then attempted to duplicate what you did but still it doesn't work. For a start my 'plane' mesh object is filled with white color unlike yours which is an empty 'box' which makes me wonder if I have done something wrong there). Then I added modifier Geometry which I had missed earlier. I attempt to check the nodes (click on Shading) there are no nodes displayed. – John Arnold Nov 20 '21 at 03:49
  • Don't bother with the Geometry Nodes option, follow the first solution using only modifiers, it is much easier to get working. Mine displays as a wire for illustration purposes, I didn't explain the steps to achieve that, it isn't supposed to look like that by default. – Duarte Farrajota Ramos Nov 20 '21 at 04:26
  • Let us continue this discussion in chat. – John Arnold Nov 20 '21 at 05:46