How to add/subtract a perfectly spherical shape to/from a surface?

[gumboyaya]

Hi there,

I guess this question might have come up from time to time but I find it to be really difficult to successfully search these forums, so here we go: I always wondered how you would add or subtrct a perfect spherical shape to/from a surface. For example if you are about to model an eyeball like that: 

I tried with the boolean/remeshing function … no success - the resulting geometry was wobbly and way too smooth.

I tried with the clipping brushes but wasn’t able to cut out a spherical shape, only cylindrical.

I tried with InsertMeshBrush but it does not seem to be possible to subtract a mesh with this one.

I am a bit stuck here. What would be the right technique the get a clean and topologically more or less useable result?

Thanks for any help in advance!

[zber2]

1. Draw your sphere, go into edit mode and make it a polymesh 3D and subdivide it to level 5, then rotate it to a side view.

2. Mask off the large portion of the sphere.

3. Open Polygroups submenu and click on Groups from masking.

4. Go to subtools and do a Groups Split.

5. Select the small portion of the sphere.

6. Go to Display Properties and flip its normals.

7. With the small portion still selected, go to Deformations subpalette and select Rotate, Y axis and type in 180.

8. Using Offset on the Z axis, move the small portion so it lines up with the hole in the large portion.

9. Rotating your view on a 45* angle will help you to visually line it up. When your getting close, it is easier to type in small values in the Offset than trying to move the slider.

10. Once it’s all lined up, go back to subtools and do Merge Visible and make sure Weld is active.

11. You now have a complete Merged tool in your tool palette.

That’s it!

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[gumboyaya]

Wow, thanks for the elaborate solution! Though this is require a bunch of steps to get there and maybe is already a bit more perfect than I meant

Is there no brush that can do similar? Like with a DragRect stroke and a “spherical” alpha? I already tried that but I think I didn’t find the right brush or brush settings, since either the bulge or hole is almost not recognizable or way to exaggerated and distorted.

I am rather looking for an intuitive way to model quick but still spherical looking blobs or dents. They don’t need to be absolutely perfect but nicely blobby

But thanks again for your workflow … might come in handy sometimes!

[aurick]

Another approach is to use Projection Master.

Drop your model to the canvas using Projection Master. Have the Deformation option turned on with Normalized turned off. (You can also turn off the options for colors.)

Now draw a Sphere3D with Zsub active. You will probably also want to lower the Z intensity (unless you want a true sphere cut out). Position it how you want over the original object, then turn off the gyro.

Now use Projection Master to pick up again.

Done!

If you’re not happy with the results you can press Ctrl+Z to undo and then drop again for another go.