diff --git a/app/jobs/activity/creator_added_model_job.rb b/app/jobs/activity/creator_added_model_job.rb
index 42c47949d..6c0246855 100644
--- a/app/jobs/activity/creator_added_model_job.rb
+++ b/app/jobs/activity/creator_added_model_job.rb
@@ -3,6 +3,20 @@ class Activity::CreatorAddedModelJob < ApplicationJob
 
   def perform(model_id)
     model = Model.find(model_id)
+    if model.public?
+      Federails::Activity.create!(
+        actor: model.creator&.actor || model.actor,
+        action: "Create",
+        entity: model
+      )
+    end
+    # Post a comment as well, for notes
+    post_comment(model)
+  end
+
+  private
+
+  def post_comment(model)
     Comment.create!(
       system: true,
       commentable: model,
diff --git a/app/models/comment.rb b/app/models/comment.rb
index 4f4f7f8e9..a32ebea4c 100644
--- a/app/models/comment.rb
+++ b/app/models/comment.rb
@@ -37,7 +37,10 @@ def to_activitypub_object
       attributedTo: (commenter&.actor&.respond_to?(:federated_url) ? commenter.actor.federated_url : nil),
       sensitive: sensitive,
       to: ["https://www.w3.org/ns/activitystreams#Public"],
-      cc: [commenter.actor.followers_url],
+      cc: [
+        commenter.actor&.followers_url,
+        commentable.actor&.followers_url
+      ],
       tag: tags
     }.compact
   end
diff --git a/app/models/model.rb b/app/models/model.rb
index 6c0055c7b..989bb088a 100644
--- a/app/models/model.rb
+++ b/app/models/model.rb
@@ -152,6 +152,33 @@ def split!(files: [])
     new_model
   end
 
+  def federated_url
+    return nil unless public?
+    Rails.application.routes.url_helpers.url_for(self, {only_path: false})
+  end
+
+  def to_activitypub_object
+    # We define a 3DModel object type, following the naming of https://schema.org/3DModel
+    # This is described in our ActivityPub docs at https://manyfold.app/technology/activitypub.html
+    {
+      id: federated_url,
+      type: "3DModel",
+      published: created_at&.iso8601,
+      attributedTo: (creator&.actor&.respond_to?(:federated_url) ? creator.actor.federated_url : nil),
+      sensitive: sensitive,
+      to: ["https://www.w3.org/ns/activitystreams#Public"],
+      cc: [
+        creator&.actor&.followers_url,
+        collection&.actor&.followers_url,
+        actor&.followers_url
+      ].compact
+    }.compact
+  end
+
+  def public?
+    Pundit::PolicyFinder.new(Model).policy.new(nil, self).show?
+  end
+
   private
 
   def normalize_license
diff --git a/app/views/models/show.activitypub.jbuilder b/app/views/models/show.activitypub.jbuilder
new file mode 100644
index 000000000..fe60ee3e5
--- /dev/null
+++ b/app/views/models/show.activitypub.jbuilder
@@ -0,0 +1,2 @@
+json.set! "@context", "https://www.w3.org/ns/activitystreams"
+json.merge! @model.to_activitypub_object
diff --git a/spec/models/model_spec.rb b/spec/models/model_spec.rb
index 9892bc3b0..03b94c1f9 100644
--- a/spec/models/model_spec.rb
+++ b/spec/models/model_spec.rb
@@ -427,4 +427,47 @@
       expect(Activity::CreatorAddedModelJob).to have_been_enqueued.with(model.id).at_least(:once)
     end
   end
+
+  context "when serializing to an ActivityPub Note" do
+    let(:creator) { create(:creator) }
+    let(:collection) { create(:collection) }
+    let(:model) { create(:model, sensitive: true, creator: creator, collection: collection) }
+    let(:ap_object) { model.to_activitypub_object }
+
+    it "creates a 3DModel" do
+      expect(ap_object[:type]).to eq "3DModel"
+    end
+
+    it "includes id" do
+      expect(ap_object[:id]).to eq model.federated_url
+    end
+
+    it "includes publication time" do
+      expect(ap_object[:published]).to be_present
+    end
+
+    it "includes sensitive flag" do
+      expect(ap_object[:sensitive]).to be true
+    end
+
+    it "includes attribution" do
+      expect(ap_object[:attributedTo]).to eq creator.actor.federated_url
+    end
+
+    it "includes to field" do
+      expect(ap_object[:to]).to include "https://www.w3.org/ns/activitystreams#Public"
+    end
+
+    it "includes model followers in cc field" do
+      expect(ap_object[:cc]).to include model.actor.followers_url
+    end
+
+    it "includes creator followers in cc field" do
+      expect(ap_object[:cc]).to include model.creator.actor.followers_url
+    end
+
+    it "includes collection followers in cc field" do
+      expect(ap_object[:cc]).to include model.collection.actor.followers_url
+    end
+  end
 end