diff --git a/README.md b/README.md
index 68824a0..084e934 100644
--- a/README.md
+++ b/README.md
@@ -57,11 +57,11 @@ const UnitTestSCAD = require('unittestscad');
 
 ```javascript
 const cube = new UnitTestSCAD.ThreeDModule({
-  include: 'cube.scad'
+  include: ['cube.scad']
 });
 
 cube.height === 5;
 ```
 
 # API Reference
-See [API Documentation](https://hopefulllama.github.io/UnitTestSCAD/) for more details.
\ No newline at end of file
+See [API Documentation](https://hopefulllama.github.io/UnitTestSCAD/) for more details.
diff --git a/src/api/AbstractParent.js b/src/api/AbstractParent.js
index 469c6b9..742e9f5 100644
--- a/src/api/AbstractParent.js
+++ b/src/api/AbstractParent.js
@@ -11,6 +11,7 @@ function sanitise(options) {
     include: valueOrDefault(options, 'include', []),
     setUpText: valueOrDefault(options, 'setUpText', ''),
     testText: valueOrDefault(options, 'testText', ''),
+    setVariables: valueOrDefault(options, 'setVariables', [])
   };
 }
 
@@ -21,6 +22,7 @@ function sanitise(options) {
  * @property {String[]} include List of .scad files to import as 'include'.
  * @property {String} setUpText Any required OpenSCAD code to set up the test.
  * @property {String} testText The OpenSCAD code to be tested and asserted on.
+ * @property {String[]} setVariables Variables to set in openscad.
  */
 
 /**
@@ -31,6 +33,6 @@ module.exports = class {
   constructor(dirtyOptions, fileType) {
     const options = sanitise(dirtyOptions);
     const header = getHeader(options.openSCADDirectory, options.use, options.include);
-    this.output = fileType.execute(header, options.setUpText, options.testText);
+    this.output = fileType.execute(header, options.setUpText, options.testText, options.setVariables);
   }
-};
\ No newline at end of file
+};
diff --git a/src/file/File.js b/src/file/File.js
index f15400e..86eb34c 100644
--- a/src/file/File.js
+++ b/src/file/File.js
@@ -9,8 +9,8 @@ function writeSCADFile(header, setUpText, testText) {
   fs.writeFileSync(scadFile, contents);
 }
 
-function executeOpenSCAD(tempFile) {
-  const command = `openscad -o ${tempFile} ${scadFile}`;
+function executeOpenSCAD(tempFile, variables) {
+  const command = `openscad -o ${tempFile} ${variables.reduce((acc,item)=>" -D "+item[0]+"=\""+item[1]+acc+"\"", "")} ${scadFile}`;
   const out = execSync(command).toString();
   const file = fs.readFileSync(tempFile, 'utf-8');
   return {
@@ -29,7 +29,7 @@ module.exports = {
   execute(options, tempOutput) {
     writeSCADFile(options.header, options.setUpText, options.testText);
     try {
-      return executeOpenSCAD(tempOutput);
+      return executeOpenSCAD(tempOutput, options.setVariables);
     } catch(error) {
       throw error;
     } finally {
@@ -37,4 +37,4 @@ module.exports = {
       safeUnlink(scadFile);
     }
   }
-};
\ No newline at end of file
+};
diff --git a/src/file/ThreeDModuleFile.js b/src/file/ThreeDModuleFile.js
index 7ffcd7f..e423e64 100644
--- a/src/file/ThreeDModuleFile.js
+++ b/src/file/ThreeDModuleFile.js
@@ -3,11 +3,12 @@ const File = require('./File');
 const stlFile = 'UnitTestSCAD_48967_TEMP_DELETE-ME_THREE_D.stl';
 
 module.exports = {
-  execute(header, setUpText, testText) {
+  execute(header, setUpText, testText, setVariables) {
     return File.execute({
       header,
       setUpText,
       testText,
+      setVariables,
     }, stlFile).file;
   }
 };
diff --git a/src/file/TwoDModuleFile.js b/src/file/TwoDModuleFile.js
index 76db034..b9755d0 100644
--- a/src/file/TwoDModuleFile.js
+++ b/src/file/TwoDModuleFile.js
@@ -3,11 +3,12 @@ const File = require('./File');
 const svgFile = 'UnitTestSCAD_48967_TEMP_DELETE-ME_TWO_D.svg';
 
 module.exports = {
-  execute(header, setUpText, testText) {
+  execute(header, setUpText, testText, setVariables) {
     return File.execute({
       header,
       setUpText,
       testText,
+      setVariables,
     }, svgFile).file;
   }
-};
\ No newline at end of file
+};