diff --git a/.gitignore b/.gitignore
index 6c871484..b5872a75 100644
--- a/.gitignore
+++ b/.gitignore
@@ -37,3 +37,5 @@ data/ram_air_kite/ram_air_kite_foil_cd_polar.csv
 data/ram_air_kite/ram_air_kite_foil_cm_polar.csv
 output/
 output_cairo/
+examples_cp/.CondaPkg/
+LocalPreferences.toml
diff --git a/CHANGELOG.md b/CHANGELOG.md
index 4dd8fed7..ce0a34a3 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,5 +1,18 @@
 # Changelog
 
+## VortexStepMethod v3.3.4 2026-05-30
+
+### Added
+- `PlotBackend`, `MakieBackend`, `ControlPlotsBackend`, and
+  `set_plot_backend!` so applications can explicitly choose which plotting
+  extension the backend-agnostic plotting API should use
+
+### Changed
+- backend-agnostic plotting wrappers now route through the active plotting
+  backend, and each plotting extension initializes itself as the default only
+  when no backend has been selected yet
+- relaxed `ControlPlots` compatibility to include both `0.2.5` and `0.3`
+
 ## VortexStepMethod v3.3.3 2026-05-21
 
 ### Fixed
diff --git a/Project.toml b/Project.toml
index 3be70a23..95af8a15 100644
--- a/Project.toml
+++ b/Project.toml
@@ -1,7 +1,7 @@
 name = "VortexStepMethod"
 uuid = "ed3cd733-9f0f-46a9-93e0-89b8d4998dd9"
 authors = ["1-Bart-1 <bart@vandelint.net>", "Oriol Cayon and contributors"]
-version = "3.3.3"
+version = "3.3.4"
 
 [workspace]
 projects = ["examples", "examples_cp", "docs", "test"]
diff --git a/bin/install_controlplots b/bin/install_controlplots
new file mode 100755
index 00000000..ea1ded43
--- /dev/null
+++ b/bin/install_controlplots
@@ -0,0 +1,335 @@
+#!/bin/bash -eu
+# SPDX-FileCopyrightText: 2025 Uwe Fechner
+# SPDX-License-Identifier: MIT
+#
+# Install and configure matplotlib for ControlPlots.jl (via PythonCall).
+#
+# Two backends are supported:
+#   1) System Python  – uses the matplotlib package installed by Ubuntu/Debian (apt).
+#                       Fastest option; shares the system Python install.
+#   2) CondaPkg       – installs matplotlib into a pixi-managed Conda environment.
+#                       Self-contained; does not require root / sudo.
+#
+# Both options configure the Qt (qtagg) backend for interactive plot windows.
+
+print_usage() {
+    echo "Usage:"
+    echo "  ./bin/install_controlplots [--system | --conda] [-y | --yes] [-h | --help]"
+    echo ""
+    echo "Options:"
+    echo "  --system   Use the system Python and matplotlib (Ubuntu/Debian apt)"
+    echo "  --conda    Use CondaPkg (pixi) to install matplotlib"
+    echo "  -y, --yes  Non-interactive; accept defaults"
+    echo "  -h, --help Show this help message"
+}
+
+_backend=""   # "system" or "conda"
+_yes=false
+
+while [[ $# -gt 0 ]]; do
+    case $1 in
+        -h|--help)
+            print_usage
+            exit 0
+            ;;
+        --system)
+            _backend="system"
+            shift
+            ;;
+        --conda)
+            _backend="conda"
+            shift
+            ;;
+        -y|--yes)
+            _yes=true
+            shift
+            ;;
+        *)
+            echo "Unknown option: $1"
+            print_usage
+            exit 1
+            ;;
+    esac
+done
+
+# Always run from the repository root (resolve from this script location).
+SCRIPT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
+REPO_ROOT="$(cd "${SCRIPT_DIR}/.." && pwd)"
+cd "${REPO_ROOT}"
+
+CONTROLPLOTS_PROJECT="examples_cp"
+
+# ── Interactive backend selection ─────────────────────────────────────────────
+
+if [[ -z "$_backend" ]]; then
+    echo "Which matplotlib backend do you want to use for ControlPlots?"
+    echo ""
+    echo "  1) System Python  (uses Ubuntu/Debian python3-matplotlib via apt)"
+    echo "     - Requires sudo"
+    echo "     - Shares the system-wide Python installation"
+    echo ""
+    echo "  2) CondaPkg       (installs matplotlib into a pixi-managed Conda environment)"
+    echo "     - No sudo required"
+    echo "     - Self-contained; downloads ~200 MB on first use"
+    echo ""
+    if [[ "$_yes" == true ]]; then
+        _choice="2"
+        echo "Using default: 2 (CondaPkg)"
+    else
+        read -rp "Enter 1 or 2 [default: 2]: " _choice
+    fi
+    case "${_choice:-2}" in
+        1) _backend="system" ;;
+        2) _backend="conda"  ;;
+        *)
+            echo "Invalid choice. Please enter 1 or 2."
+            exit 1
+            ;;
+    esac
+fi
+
+echo ""
+echo "Selected backend: $_backend"
+echo ""
+
+# ── Helper: install matplotlib via CondaPkg ───────────────────────────────────
+
+_install_matplotlib_condapkg() {
+    echo "Installing matplotlib and pyqt into CondaPkg (pixi) environment..."
+    julia --project="${CONTROLPLOTS_PROJECT}" -e '
+using Pkg
+# Ensure CondaPkg is available
+if Base.find_package("CondaPkg") === nothing
+    Pkg.add("CondaPkg")
+end
+using CondaPkg
+CondaPkg.add("matplotlib")
+CondaPkg.add("pyqt")
+CondaPkg.resolve()
+println("matplotlib and pyqt installed in CondaPkg environment.")
+'
+}
+
+_verify_controlplots() {
+    echo "Verifying ControlPlots can be loaded..."
+    local _julia_prefix=""
+    if [[ "$(uname -s)" == "Linux" ]]; then
+        _julia_prefix="env -u LD_PRELOAD -u LD_LIBRARY_PATH"
+    fi
+    if $_julia_prefix julia --project="${CONTROLPLOTS_PROJECT}" -e '
+using ControlPlots
+println("ControlPlots loaded successfully.")
+'; then
+        echo ""
+        echo "✓ ControlPlots is working."
+    else
+        echo ""
+        echo "Warning: ControlPlots could not be loaded. Check the error output above."
+        echo "You may need to run this script again with the other backend option."
+        exit 1
+    fi
+}
+
+# ── Helper: write MPLBACKEND=qtagg to LocalPreferences.toml ──────────────────
+
+_set_mplbackend_qtagg() {
+    local _prefs_file="${CONTROLPLOTS_PROJECT}/LocalPreferences.toml"
+    # Remove any existing [ENV] section managed by this script.
+    if [[ -f "$_prefs_file" ]]; then
+        _tmp=$(mktemp)
+        awk '
+            /^\[ENV\]/ { in_env=1; next }
+            in_env && /^\[/ { in_env=0 }
+            !in_env { print }
+        ' "$_prefs_file" > "$_tmp"
+        mv "$_tmp" "$_prefs_file"
+    fi
+    {
+        echo ""
+        echo "[ENV]"
+        echo "MPLBACKEND = \"qtagg\""
+    } >> "$_prefs_file"
+    echo "Set MPLBACKEND=qtagg in $_prefs_file."
+}
+
+# ── System Python backend ─────────────────────────────────────────────────────
+
+if [[ "$_backend" == "system" ]]; then
+    # Detect package manager and install python3-matplotlib if missing.
+    if [[ "$(uname -s)" == "Linux" ]]; then
+        if grep -qiE "ubuntu|debian" /etc/os-release 2>/dev/null; then
+            if ! dpkg -s python3-matplotlib &>/dev/null 2>&1 || ! dpkg -s python3-pyqt5 &>/dev/null 2>&1; then
+                echo "Installing python3-matplotlib and python3-pyqt5 via apt..."
+                sudo apt install -y python3-matplotlib python3-pyqt5
+            else
+                echo "python3-matplotlib and python3-pyqt5 are already installed."
+            fi
+        elif grep -qi "fedora" /etc/os-release 2>/dev/null; then
+            if ! rpm -q python3-matplotlib &>/dev/null 2>&1 || ! rpm -q python3-pyqt5 &>/dev/null 2>&1; then
+                echo "Installing python3-matplotlib and python3-qt5 via dnf..."
+                sudo dnf install -y python3-matplotlib python3-pyqt5
+            else
+                echo "python3-matplotlib and python3-pyqt5 are already installed."
+            fi
+        else
+            echo "Warning: Could not detect Ubuntu/Debian or Fedora."
+            echo "Please ensure python3-matplotlib is installed manually before continuing."
+            if [[ "$_yes" == false ]]; then
+                read -rp "Continue anyway? (y/n) [default: y]: " _cont
+                case "${_cont:-y}" in
+                    n|N) echo "Aborted."; exit 1 ;;
+                esac
+            fi
+        fi
+    elif [[ "$(uname -s)" =~ ^(MINGW|MSYS|CYGWIN) ]]; then
+        # Windows (Git Bash): use pip to install matplotlib and PyQt5.
+        _pip=""
+        for _pip_candidate in pip3 pip; do
+            if command -v "$_pip_candidate" &>/dev/null; then
+                _pip="$_pip_candidate"
+                break
+            fi
+        done
+        if [[ -n "$_pip" ]]; then
+            if ! "$_pip" show matplotlib &>/dev/null 2>&1 || ! "$_pip" show PyQt5 &>/dev/null 2>&1; then
+                echo "Installing matplotlib and PyQt5 via pip..."
+                "$_pip" install --user matplotlib PyQt5
+            else
+                echo "matplotlib and PyQt5 are already installed."
+            fi
+        else
+            echo "Warning: pip not found. Please install matplotlib and PyQt5 manually:"
+            echo "  pip install matplotlib PyQt5"
+            if [[ "$_yes" == false ]]; then
+                read -rp "Continue anyway? (y/n) [default: y]: " _cont
+                case "${_cont:-y}" in
+                    n|N) echo "Aborted."; exit 1 ;;
+                esac
+            fi
+        fi
+    else
+        echo "Warning: System Python backend is intended for Ubuntu/Debian/Fedora Linux or Windows."
+        echo "On this OS ($(uname -s)) you may need to install matplotlib manually."
+        if [[ "$_yes" == false ]]; then
+            read -rp "Continue anyway? (y/n) [default: y]: " _cont
+            case "${_cont:-y}" in
+                n|N) echo "Aborted."; exit 1 ;;
+            esac
+        fi
+    fi
+
+    # Locate the system python3 executable.
+    _syspython=""
+    if [[ "$(uname -s)" =~ ^(MINGW|MSYS|CYGWIN) ]]; then
+        # On Windows (Git Bash) 'python3' may not exist; also try 'python'.
+        for _candidate in python3 python; do
+            if command -v "$_candidate" &>/dev/null; then
+                _syspython=$(command -v "$_candidate")
+                # Verify it runs (guards against the Windows Store stub).
+                if "$_syspython" --version &>/dev/null 2>&1; then
+                    break
+                fi
+                _syspython=""
+            fi
+        done
+    else
+        for _candidate in python3 /usr/bin/python3; do
+            if command -v "$_candidate" &>/dev/null; then
+                _syspython=$(command -v "$_candidate")
+                break
+            fi
+        done
+    fi
+    if [[ -z "$_syspython" ]]; then
+        echo "Error: python3 not found on PATH. Please install python3."
+        exit 1
+    fi
+    echo "Found system Python: $_syspython"
+
+    # Remove the CondaPkg-managed environment so that PythonCall won't keep
+    # using a stale conda Python when switching to system Python.
+    if [[ -d "${CONTROLPLOTS_PROJECT}/.CondaPkg" ]]; then
+        echo "Removing ${CONTROLPLOTS_PROJECT}/.CondaPkg (switching from CondaPkg to system Python)..."
+        rm -rf "${CONTROLPLOTS_PROJECT}/.CondaPkg"
+    fi
+    # Unset JULIA_PYTHONCALL_EXE so the LocalPreferences.toml exe setting takes
+    # effect.
+    unset JULIA_PYTHONCALL_EXE
+    # Prevent CondaPkg from re-installing a Conda env in the current process.
+    export JULIA_CONDAPKG_BACKEND="Null"
+    export JULIA_PYTHONCALL_EXE="$_syspython"
+
+    # Helper: update a LocalPreferences.toml file with the system Python settings.
+    _write_system_python_prefs() {
+        local _pf="$1"
+        if [[ -f "$_pf" ]]; then
+            _tmp=$(mktemp)
+            awk '
+                /^\[PythonCall\]/ { in_sec=1; next }
+                /^\[PyCall\]/ { in_sec=1; next }
+                /^\[CondaPkg\]/ { in_sec=1; next }
+                in_sec && /^\[/ { in_sec=0 }
+                !in_sec { print }
+            ' "$_pf" > "$_tmp"
+            mv "$_tmp" "$_pf"
+        fi
+        {
+            echo ""
+            echo "[PythonCall]"
+            echo "exe = \"$_syspython\""
+            echo ""
+            echo "[CondaPkg]"
+            echo "backend = \"Null\""
+        } >> "$_pf"
+        echo "Written to $_pf."
+    }
+
+    echo ""
+    echo "Saving python_exe=$_syspython to LocalPreferences.toml files..."
+    # Write to both the root project and examples_cp project, because
+    # `julia --project=examples_cp` reads examples_cp/LocalPreferences.toml,
+    # not the root one.
+    _write_system_python_prefs "LocalPreferences.toml"
+    _write_system_python_prefs "${CONTROLPLOTS_PROJECT}/LocalPreferences.toml"
+
+    _set_mplbackend_qtagg
+    _verify_controlplots
+
+    echo ""
+    echo "Done. ControlPlots will use the system Python (PythonCall) matplotlib with the Qt (qtagg) backend."
+
+# ── CondaPkg backend ──────────────────────────────────────────────────────────
+
+elif [[ "$_backend" == "conda" ]]; then
+    # Remove [PythonCall] exe, [CondaPkg] backend override, and legacy [PyCall]
+    # so PythonCall falls back to the CondaPkg-managed Python.
+    # Must be done in both the root and examples_cp LocalPreferences.toml.
+    _remove_python_prefs() {
+        local _pf="$1"
+        [[ -f "$_pf" ]] || return 0
+        _tmp=$(mktemp)
+        awk '
+            /^\[PythonCall\]/ { in_sec=1; next }
+            /^\[PyCall\]/ { in_sec=1; next }
+            /^\[CondaPkg\]/ { in_sec=1; next }
+            in_sec && /^\[/ { in_sec=0 }
+            !in_sec { print }
+        ' "$_pf" > "$_tmp"
+        if ! diff -q "$_pf" "$_tmp" &>/dev/null; then
+            mv "$_tmp" "$_pf"
+            echo "Removed [PythonCall]/[CondaPkg] sections from $_pf (switching to CondaPkg)."
+        else
+            rm -f "$_tmp"
+        fi
+    }
+    _remove_python_prefs "LocalPreferences.toml"
+    _remove_python_prefs "${CONTROLPLOTS_PROJECT}/LocalPreferences.toml"
+
+    _install_matplotlib_condapkg
+
+    _set_mplbackend_qtagg
+    _verify_controlplots
+
+    echo ""
+    echo "Done. ControlPlots will use the CondaPkg-managed matplotlib with the Qt (qtagg) backend."
+fi
diff --git a/test/Project.toml b/test/Project.toml
index 229362d1..8ca3f410 100644
--- a/test/Project.toml
+++ b/test/Project.toml
@@ -29,7 +29,7 @@ Aqua = "0.8"
 BenchmarkTools = "1"
 CSV = "0.10"
 CairoMakie = "0"
-ControlPlots = "0.2.5"
+ControlPlots = "0.2.5, 0.3"
 DataFrames = "1.7"
 Documenter = "1.8"
 Interpolations = "0.15, 0.16"