Creating a new layer and renaming automatically using Python script


I was wondering if anybody can show me how to add a new layer and label it automatically. For example, create a new layer and name it layer01. Then run the script again and it will create a new layer and label it layer02 and so on.

Below is some script I found that creates a new layer but I have to name it myself. I have approx 160 layers to create and name so was hoping to do this automatically.

Can anyone help please?


import Rhino
import scriptcontext 
import System.Guid, System.Drawing.Color

def AddLayer():
    # Cook up an unused layer name
    unused_name = scriptcontext.doc.Layers.GetUnusedLayerName(False)

    # Prompt the user to enter a layer name
    gs = Rhino.Input.Custom.GetString()
    gs.SetCommandPrompt("Name of layer to add")
    if gs.CommandResult()!=Rhino.Commands.Result.Success:
        return gs.CommandResult()

    # Was a layer named entered?
    layer_name = gs.StringResult().Trim()
    if not layer_name:
        print "Layer name cannot be blank."
        return Rhino.Commands.Result.Cancel

    # Is the layer name valid?
    if not Rhino.DocObjects.Layer.IsValidName(layer_name):
        print layer_name, "is not a valid layer name."
        return Rhino.Commands.Result.Cancel

    # Does a layer with the same name already exist?
    layer_index = scriptcontext.doc.Layers.Find(layer_name, True)
    if layer_index>=0:
        print "A layer with the name", layer_name, "already exists."
        return Rhino.Commands.Result.Cancel

    # Add a new layer to the document
    layer_index = scriptcontext.doc.Layers.Add(layer_name, System.Drawing.Color.Black)
    if layer_index<0:
        print "Unable to add", layer_name, "layer."
        return Rhino.Commands.Result.Failure

    return Rhino.Commands.Result.Success

if __name__=="__main__":

FYI I edited your post to enclose your code in triple backticks:


That way you get properly formatted code on our Discourse forum.


Hi @David_Gibbins,

Not exactly sure what you are looking for. Maybe this help?

import Rhino
import scriptcontext as sc

def test_add_layers():
    color = Rhino.ApplicationSettings.AppearanceSettings.DefaultLayerColor
    for i in range(0, 160):
        name = sc.doc.Layers.GetUnusedLayerName()
        sc.doc.Layers.Add(name, color)
if __name__ == '__main__':    

– Dale

1 Like

Hi Dale,

Thanks for replying back so quickly.

That’s exactly what I’m after (almost). Instead of the new layers being named ‘Layer 1’, ‘Layer 2’ etc, how can I change the name to ‘Extract 1’, ‘Extract 2’ etc. and also to change the layer to colour it red?

Apologies, I should have put this in my original query but didn’t want to overload the question too early and I thought I could figure it out. I’m quite new to Python scripting and still learning.

Thanks again for your help.

Here you go:

import System
import Rhino
import scriptcontext as sc

def _get_unused_name(prefix):
    number = 1
    while True:
        number_str = str(number)
        name = "{0} {1}".format(prefix, number_str.zfill(2))
        layer = sc.doc.Layers.FindName(name)
        if layer:
            number += 1
            return name

def test():
    color = System.Drawing.Color.Red
    for i in range(0, 160):
        name = _get_unused_name("Extract")
        sc.doc.Layers.Add(name, color)

if __name__ == '__main__':

– Dale

1 Like

That’s great. It works a treat. Thanks so much Dale.