showing error info for invalid boolean results

web/app/3d/craft/brep/wizards/wizard.js

@@ -1,5 +1,6 @@
 import * as tk from '../../../../ui/toolkit'
 import {camelCaseSplit} from '../../../../utils/utils'
+import {isTCADError} from "../../../../utils/errors";
 
 export class Wizard {
 
@@ -46,6 +47,7 @@ export class Wizard {
     }
     const buttons = new tk.ButtonRow(["Cancel", "OK"], [() => this.cancelClick(), () => this.okClick()]);
     tk.add(folder, buttons);
+    tk.add(folder, {root: $('<div class="errors-message" />')});
     box.root.keydown((e) => {
       switch (e.keyCode) {
         case 27 : this.cancelClick(); break;
@@ -61,12 +63,32 @@ export class Wizard {
   }
 
   okClick() {
-    this.dispose();
-    this.apply();
+    if (this.apply()) {
+      this.dispose();
+    }
   }
 
   apply() {
-    this.app.craft.modify(this.createRequest(), this.overridingHistory);
+    let errors = this.app.craft.modify(this.createRequest(), this.overridingHistory);
+    if (errors) {
+      this.showErrors(errors);
+      return false;
+    } else {
+      return true;
+    }
+  }
+
+  showErrors(error) {
+    this.showErrorText('performing operation with current parameters leads to an invalid object' +
+      '(manifold / self-intersecting / zero-thickness / complete degeneration or unsupported cases)');
+    if (!isTCADError(error)) {
+      console.error('internal error while performing operation');
+      throw error;
+    }
+  }
+
+  showErrorText(message) {
+    this.box.root.find('.errors-message').text(message);  
   }
 
   onUIChange() {}

web/app/3d/craft/craft.js

@@ -67,7 +67,12 @@ Craft.prototype.modifyInternal = function(request) {
   var op = this.operations[request.type];
   if (!op) return;
 
-  const result = op(this.app, request.params);
+  let result;
+  try {
+    result = op(this.app, request.params);
+  } catch(err) {
+    return err;
+  }
 
   for (let solid of result.outdated) {
     solid.vanish();
@@ -89,7 +94,10 @@ Craft.prototype.modifyInternal = function(request) {
 };
 
 Craft.prototype.modify = function(request, overriding) {
-  this.modifyInternal(request);
+  let errors = this.modifyInternal(request);
+  if (errors !== undefined) {
+    return errors;
+  }
   if (!overriding && this._historyPointer != this.history.length) {
     this.history.splice(this._historyPointer + 1, 0, null);
   }

web/app/utils/errors.js

@@ -11,6 +11,6 @@ export default class CadError extends Error {
     super(code);
     this.code = code;
     this.payload = payload;
+    this.type = ERROR_TYPE;
   }
 }
-CadError.prototype.type = ERROR_TYPE;

web/css/app3d.less

@@ -290,4 +290,9 @@ iframe {
 
 .history-selected .modification-right-buttons, .modification-item:hover .modification-right-buttons {
   display: initial;
+}
+
+.errors-message {
+  padding: 5px;
+  color: lightgoldenrodyellow;
 }