Instructions for using the Tinsellator

This Geometry node tree is offered here as a tool to create strands of tinsel. However it can be hacked to either spread tinsel over any geometry with points or alternatively to spread any geometry over any other geometry.

Here’s how to use it responsibly.

Open the tinsel blend file. You can either create your tinsel within this file and copy the tinsel into your scene, or if you want to create tinsel directly in your scene, copy and paste the sample tinsel strand into your file so that the Geometry nodes are copied with it. In the second case you will also need the collection of appropriate strands that you intend to utilise from the Outliner.

Tinsel Creation:

1)      Add a Bezier Curve. Extend and manipulate the curve to create the tinsel strand of your dreams. You’ll be able to edit it later so don’t be too fussy. Use as many points as you want, but follow the mantra ‘Less is more’.

2)      Go over to the Properties panel and click on the Modifiers tab (Spanner)

3)      Make sure your Bezier curve is selected in Object Mode and click ‘Add Modifier’. Select Geometry Nodes from the Generate column. Once the Geometry Nodes Modifier appears, from the dropdown list to the left of the Add New button choose ‘Tinsellator’ from the list. Your Bezier curve should now be tinseled.

4)      The Modifier tab now contains a box for the Geometry Nodes Tree that gives you control over the look and feel of the tinsel. Here you can adjust the tinsel to your satisfaction

a.       Selection – Select 0 off or 1 on for tinsel or not. ** see also note lower down

b.      Scale – Sets the overall size of the tinsel strands

c.       Scale Variance – Sets how shaggy the strand looks. Use this in concert with Scale to get the look you are aiming at.

d.      Tinsel Type - Use this to change between colours by pointing it to the appropriate collection of strands in the Outliner. (Set it to any collection but DO NOT set it to the collection containing your tinsel strand (or any collection that is a parent of the strands collection). This will make Blender populate the strand with strands of itself, creating a recursive loop that will continue until the computer freezes.)

e.      Strands per cm - Literally the number of strands along your tinsel per cm. You will need more for a fuller denser look, less if you want it to look more moth-eaten. 10 to 40 is about right.

Don’t forget, whilst in the original Blend file you can swap between tinsel colours unfettered. However, if you use the Geometry nodes in another file you will only be able to access those colours whose Collections you have copied into that file

If creating tinsel alone isn’t enough fun and you want to go off-piste, here are a few things you can do.

For more colours there a couple of ways to do your own thing. Go to the Outliner and look for the Strand collections. You’ll find one for each of my colours. The easiest thing to do is to pick up a strand from the colour you are using and alter the diffuse colour of its material. Better still create a new material and alter that as often more than one Tinsel shares a material, so altering a colour may have unexpected consequences. Don’t be held to my settings, feel free to alter anything to achieve a result you like. If you want to preserve the file as it is, take a whole collection (ie Tinsel Green and Red) and copy it and its contents to a new collection. Alter this and then select it as in 4d. above to apply it to your strand.

You don’t actually need to use a Bezier curve, the Geometry nodes applied to any shape will add tinsel strands on the points of that shape. In this case the strand count won’t work as that acts on a curve only. Careful though, it can get a bit memory heavy as you need to do a lot of subdivisions to get enough points to create a well tinselled look. ** A footnote to earlier – If you click the spreadsheet button (Like a flag) to the left of the 0 or 1, the text will disappear. If you then click in the empty box you get a list of items. If you have assigned some of your geometry a Vertex Group, they will appear here and you can select them. The tinsel will then only be applied to the vertices in this group. You will probably have to sub-divide the mesh to get enough vertices, but you will have to Apply the sub-division before the Geometry nodes work as required.

Additionally any geometry added to one of the strand collections will distribute itself just as the tinsel strands do. The strands are quite simple so things work. Add something into a collection that itself has a lot of geometry and the multiplication can soon make a very very large file.

Notes

These Geometry nodes work in all versions of Blender from 3.1 onwards with just a minor loss of functionality owing to 1 Geometry node (Sample nearest Surface) which is used aligning strands to surface normals. This only impacts when tinsel is spread over mesh Geometry. Curves are unaffected as this part of the node tree does not function on a curve anyway. To function perfectly needs version 3.4