As regular forum participants may know, I’ve been working with Scott Baker (@NewThinking2) on a very large and complex SU model. To give you an idea of scale, it is currently (in round numbers) about 270MB, has 27 million edges, over 11 million faces, 560,000 component instances, 5,500 component definitions, and 60,000 groups (mostly imported 3D warehouse models - they could probably usefully be converted to components).
One particularly resource hungry type of component is a Dynamic Component Railing. It is widely used in the model tor terrace railings, of which there are several hundred sets, some quite long with many vertical spindles. This adds dramatically to the edge count, and can drastically slow down not only modelling, but even viewing when you try to orbit or zoom, once SU has too many to deal with.
Here’s a typical example:
In typical DC fashion, you use the Scale tool to adjust the length, and the number of spindles adjusts to fit, keeping a constant spacing:
I wanted to create a much simpler component, to avoid both the high number of edges in the full ‘solid’ railing, and the per-component overhead of a DC which seems to be about 5KB.
So I have devised a simpler structure, one version with and the other without corner posts.
They use a small image of the spindle as a repeating element in a texture applied to a face between top and bottom rails and the posts, or blank ends for the short cross railings.
This is made from a screenshot of a solid railing (image on the left), saved as a PNG file, and modified to have a transparent background (image on the right)using Preview/Instant Alpha on a Mac, or some equivalent image editor on Windows.
I then imported this image as a texture, and applied it to a face in the simplified railing component, which is loose geometry inside a single-level component.
Turn on View Hidden Geometry to make the edges of the face visible, and able to be acted upon by the Move tool, and you have a lightweight component which behaves much like a DC. To change the length, window select round the end post and the end of the face with the textured image, and Move along the axis.
Even close up, from the right viewing angle, it’s hard to tell the difference between the simplified and the original versions
And here’s the SKP file (saved back to v8):
[EDIT] I forgot to purge the file uploaded earlier - here’s the purged and MUCH smaller version - just 53KB.
Terrace railings - imaged.skp (52.9 KB)
The equivalent 3-railing set of DC railings is about 290KB.
The DC railing set has (again, in round numbers) 1600 edges, 800 faces, and 130 component definitions (of which, most are copies of the spindle, but separate definitions, not just instances).
The imaged version has fewer than 160 edges, 70 faces, 3 component instances and 2 definitions (two types of railing, one with, and one without, corner posts).
At a distance, the imaged version doesn’t appear so ‘heavy’ visually (even with Profile edges turned off, the DC goes almost black as the ‘real’ edges merge when you zoom out).
The windows too are a simplified version - done again mainly to reduce edge count from all the verticals. That’ll be the subject of a separate post. There are two images to give the illusion of depth as you orbit.