Cineversity

Hi!

Voronoi Fracture is a really great tool, but one thing I’ve been trying to figure out is if there is any way of easily creating more irregular/natural looking fractures, as one would find in nature when cracking real objects (stone for instance).
One way of doing this, which involves lot of manual labour, is making a Voronoi Fracture editable and then merging pieces with Connect and Delete, and then going in and deleting all the inner polygons (see attachment for example of this and also a real image of cracked stone), but as this is quite a time consuming process I was just curious as to whether there might be some other way of achieving this, which also preferably preserves the parametric nature of a Voronoi Fracture.

Kind Regards
Andreas Wolmer

Hi Andreas Wolmer,

Think of the edges (and flat areas) created in Voronoi as the representation of an mid- distance between points. Two points become connected and perpendicular to that line, exactly between the points is set a cutting plane. Other point-pairs do the same and the shortest distance of point-pairs always wins. This is the “idea” behind Voronoi, at least how I understand it.

A little bit more detailed:
https://en.wikipedia.org/wiki/Voronoi_diagram
The manhattan example is limited to straight or 45º lines, perhaps, one day we get a noisy line cut, but with a spatial cut like that, perhaps the polygons created have some problems, as some have in my “example” already.

It is not a noise formula that cuts where the contrast of mid gray point of the noise would be, even it might looks in a way like that.

As in your example, here are some other ideas
https://www.amazon.com/clouddrive/share/SWSvhNcGGH0M69Vx1jOD79GSRcElgJVU7xfGBIttdt0?ref_=cd_ph_share_link_copy

BTW:
A while ago I made these two little clips. Yes, not voronoi based, but perhaps with R18 an alternative Part 1+2:
https://www.amazon.com/clouddrive/share/im7trZXZ9RkfOMWQ4SSs5vKVPbSSEpgez8xtEhvhKw3?ref_=cd_ph_share_link_copy
https://www.amazon.com/clouddrive/share/CWwKyzAZCBpChZ8idpm91WbGXpse5fYqH62mb8gUetG?ref_=cd_ph_share_link_copy

All the best

Hello Dr Sassi!

Thanks for the quick and helpful reply.
Ok, I understand the basic voronoi functionality and the current limitations. Your example file and the clips are very interesting and I will definitely explore the concepts there further.
I guess I will send a feature suggestion to Maxon and maybe in the future we will get even more small detail/randomisation in the Voronoi Fracture.

Thank you for your time and effort!
Kind Regards
Andreas

Hi Andreas,
Thanks for the nice feedback. Yes, a suggestion to Maxon is always great.
I travel at the moment, but I’m happy to share one more idea tomorrow, which I think could be a step towards this, but it is a little bit complex…., but I have used it I an illustration already.

My best wishes

Hi!

I am absolutely interested in seeing what else you have up your sleeve regarding this, looking forward to it!

Cheers!
Andreas

OK, Andreas, but they are a little bit of a workaround. :o) Not a click and done.

Anyway, here is the image that I did a while ago:
https://www.amazon.com/clouddrive/share/w0SoRmyjyY1cE7J1jSdoYsJC6XwopFEQnqoXwb5Hgx4?ref_=cd_ph_share_link_copy

I used a Random Effector to get a lot of points along a spline. In the image I used a MoSpline, so I was able to work on the original spline.
With a MoSelection, I “painted” over the larger chunks. This selection helped me to pull the buildings out. Imagine one would delete the buildings and have that cracked line. That was one idea. It is in the zip archive with the next scene here: (_01 is an simplified version of the image, and please note, any change will destroy the usefulness of the MoSelection. _12 is the file from the clip)
https://www.amazon.com/clouddrive/share/MkbuWESDbI5jqiL8WbLaku9mRejD3C7rFB6iEFuHE58?ref_=cd_ph_share_link_copy

The next one is perhaps much simpler. Have a look at this clip:
https://www.amazon.com/clouddrive/share/NkJeWzzckioJjAZROg9iQIq5lCPblWmMcoljAlvUT8C?ref_=cd_ph_share_link_copy

To have an edge selection helps to get a Spline. (Donavan Keith has pushed this even further in his tutorial about: https://www.cineversity.com/vidplaylist/release_18_quick_tips/model_smooth_branching_structures_with_voronoi_fracture_and_metaballs  )
My idea here is pretty much an old standard, just add details with more point, and set the distortion with noise, perhaps use a different noise pattern. To get back to the MoGraph options, use the Fracture Object.

If there is a question, please let me know

All the best

Nice! Thank you, looking forward to dissecting your files!

Cheers
Andreas

Hi Andreas,

I hope my little files will represent a good base to add your ideas and needs, or get even completely new ones. :O)

Please, never hesitate to ask, if there is anything else. There are always more ways to do it, and as I normally say, there are over thousand functions, commands and options in C4D, but the real magic starts by combining them, which seems to be a near endless number of combinations.

My best wises