Hi –

I am trying to figure out a way to get a closed, planar curve to show up in render view as a filled in region *without* converting it into a surface via `Boundary Surface`

. This may not be possible. Motivation given below.

I have a definition which does the following:

- Split a rectangular surface using a ton of planar cutting curves. This outputs a list of trimmed planar surfaces, call it
`S`

. - Uses a variety of algorithms to cull a subset of the trimmed surfaces, call it
`S'`

. - Use a variety of algorithms to split
`S'`

into two groups, call them`A`

and`B`

. -
`A`

is immediately sent to a custom preview and so all the trimmed surfaces in it show up as monochromatic filled regions in`rendered`

view. -
`B`

is not immediately rendered. Instead, it is sent to a section which, conceptually, masks each region with a “square wave” with adjustable frequency and duty cycle: think IBM logo. This is the section which I am working on optimizing right now. More details below, but first…

Here are some examples of the output with various settings for step 5.

Currently, the process for step 5 is:

- create a global collection of contour lines which are the width of the image, and spaced out according to the frequency parameter,
`f`

. - Use each line as the base of a rectangle a duty cycle parameter
`d`

to create a rectangle whose height is a percentage of the distance to the the next contour line. Call this collection of rectangles`R`

- For each trimmed surface in set
`B`

, calculate its intersection with`R`

using`Brep | Brep`

. This outputs a collection of closed curves (aka the “IBM logo effect”) for that region. This could possibly be optimized by not running the intersection on the entire set of rectangles`R`

but only ones with relevant min/max values for the bounds for the upper and lower bounds of the currently processed surface. Call the entire set of closed curves generated from this process`C`

- Convert each closed curve in
`C`

into a surface using`Boundary Surface`

so that it will show up in Rendered view as a black region.**This is the step which I want to optimize, since it is the slowest step of the entire definition and also seems overly complicated for the desired result.**

Each element in `C`

is necessarily a closed planar curve. **It seems to me that there must be a way to get a closed, planar curve to render as a filled in region in the viewport when sent to custom preview that doesn’t require the computational complexity of running them all through boundary surface.** I am dealing with hundreds or sometimes thousands of these closed curves, and so

`Boundary Surface`

can take over a second to run, whereas the rest of the entire algorithm takes less than half a second.Essentially, I would like to show a collection of closed planar curves (like those below) in render view as filled regions without first converting them to surfaces via boundary surface (since I am actually doing this for hundreds or thousands of curves.

Is there something trivial I am missing?

The entire algorithm should be pretty much real time, or close to it, and this is currently the major hurdle.