FORUMS TUTORIALS MAGAZINE STOCKYARD VIDEOS PODCASTS EVENTS SERVICES NEWSLETTER NEWS BLOGS
 MAXON CINEMA 4D: Cinema 4D Forum Cinema 4D Tutorials Cinema 4D Tag Adobe After Effects Forum

How to cut a circle in a polygon?

COW Forums : Cinema 4D

<< PREVIOUS   •   VIEW ALL   •   PRINT   •   NEXT >>
 How to cut a circle in a polygon? by Craig Ricker on Apr 20, 2012 at 5:34:50 am

Is there a way to cut a circle in a polygon? Basically I want to make a perforated piece of plastic (i.e a protective speaker covering) The circles will look similar to the front of a mac pro's casing.

 Re: How to cut a circle in a polygon?by randy johnson on Apr 21, 2012 at 7:05:58 am

With that many small holes you should just use the alpha channel in the material, with displacement. It would take a life time to model that otherwise.

/Randy

 Re: How to cut a circle in a polygon?by Siddharth Gautam Singh on Apr 21, 2012 at 1:07:00 pm

Hi,

With wide shots the alpha solution works well. I am not sure if it would work very well with closeups.

This is how I would do it:

Take a circle spline, clone it using a grid array into the desired grid you want.
Then collapse the cloner object to get the splines (you will get a null object with all the splines as children). Now if the initial circle was a parametric object, you will have to select all the circles and convert them into splines as well.
Then with all the splines selected, do connect+delete.
You will get one single gird of circles spline.
Now if you want a rectangular grid, draw a rectangle around the grid of circles.
Make the rectangle editable (if not already).
Connect the grid and rectangle together.
Apply a Extrude Nurbs modifier.

Now this solution gives you real geometry. You can also bevel the edges of the circle grid easily.

 Re: How to cut a circle in a polygon?by David Biederbeck on Apr 22, 2012 at 6:57:26 am

Recently had to create a skateboard helmet and used alpha. Thanks for the clear and precise way to actually achieve the desired result!

 Re: How to cut a circle in a polygon?by Craig Ricker on Apr 22, 2012 at 11:44:30 am

Got a link to a good tut on how I use the alpha to make such a result by any chance?

 Re: How to cut a circle in a polygon?by Siddharth Gautam Singh on Apr 25, 2012 at 7:28:08 am

Hi Craig,

This is what I achieved using an alpha map and displacement. What I did was to create a single grid cell using the extrude method and render it out. Then I used that image in the alpha and displacement channels, and then tiled it on to my model.

Tried using a normal map to get the bevel, but it was not working.

The mapping is a bit off and the displacement gets a bit crappy if you look closer, but it does a pretty good job I think.

`<a href="http://images.creativecow.net/232974/alphagridmaptest.png"><img src="http://i1.creativecow.net/u/232974/alphagridmaptest.png" border="0" /></a>`

Siddharth G Singh
Film | Motion | Illustration
http://www.siddharthgsingh.com

 Re: How to cut a circle in a polygon?by Craig Ricker on Apr 23, 2012 at 1:10:31 am

Oh and thanks Sidharth, those instructions worked beautifully for the real geometry method!

 Re: How to cut a circle in a polygon?by Craig Ricker on Apr 25, 2012 at 9:54:00 pm

Wow looks good hey! But wasn't sure what you meant by a single Grid cell with the extrude method?

 Re: How to cut a circle in a polygon?by Siddharth Gautam Singh on Apr 26, 2012 at 5:11:38 am

I basically made one hole inside a square using splines and extrusion. I used the Falloff shader in the Luminance channel to get the 'depth' pass. I used this render in the alpha and displacement channels to create the grid in the image.

This can also be achieved just using gradients too I think.

Siddharth G Singh
Film | Motion | Illustration
http://www.siddharthgsingh.com

<< PREVIOUS   •   VIEW ALL   •   PRINT   •   NEXT >>