Exchange Messages with Block Comments

Comments provide an interface for teams to review, iterate, and develop block diagrams. With comments, you can collaborate directly in the Simulink^® Editor. Team members can add comments to provide feedback, ask questions, and suggest alternative designs.

You can also use comments to record action items as you develop a block diagram. For example, you can add comments to remind yourself of design ideas and to indicate where you may need to change a parameter value.

The Comments pane contains an open comment, a resolved comment with a response, and a comment about to be resolved.

To add descriptive notes and annotations that are not actionable, see Annotate Models.

To mark up a printed copy of the block diagram, see Print Model Diagrams.

Determine Whether Model Has Open Comments

When you close a model, subsystem, or library file that has comments, the comments are saved in an MLDATX file with a _comments suffix. For example, for a model named mymodel.slx, the comments file is named mymodel_comments.mldatx. To access the comments, the corresponding comments file must be on the MATLAB^® path. When the comments file is accessible and the model has open comments, a badge () appears in the lower-left corner of the Simulink Editor canvas.

View Comments

To view comments, open the Review Manager perspective by performing one of these actions:

In the Simulink Toolstrip, on the Modeling tab, in the Design gallery, select Review Manager.
In the lower-right corner of the Simulink Editor canvas, click the perspectives control and select the Review Manager perspective.
If the model has open comments, click the Model has open review comments badge in the lower-left corner of the Simulink Editor canvas.

These actions open the Review tab and the Comments pane.

When a block has comments associated with it, a comment icon appears on the block. Click the comment icon to highlight the related comments in the Comments pane. To see the most recent comment for the block as a tooltip, pause on the comment icon.

Add Comments

To add a comment:

Open the Review Manager perspective by performing one of these actions:
- In the Simulink Toolstrip, on the Modeling tab, in the Design gallery, select Review Manager.
- In the lower-right corner of the Simulink Editor canvas, click the perspectives control and select the Review Manager perspective.
- If the model has open comments, click the Model has open review comments badge in the lower-left corner of the Simulink Editor canvas.
Select a block in the Simulink Editor canvas, then perform one of these actions:
- Pause on the ellipsis, then click the Add Comment button in the action bar.
- On the Review tab, click Add Comment.
Enter the comment in the text box that appears in the Comments pane.
To enter multiline comments in the Comments pane, press Shift+Enter while editing a comment.

When you rename a block that has comments, the Comments pane updates to display the new block name. Blocks are sorted alphabetically by name in the Comments pane. Renaming a block can change the position of the comments in the pane.

When you close the parent model, subsystem, or library file, the comments are saved in an MLDATX file in the same location as the parent. Suppose you add comments to a model named mymodel.slx, which previously had no comments associated with it. Closing the model creates a comments file named mymodel_comments.mldatx.

To add comments to blocks in other files, open the files separately. For example, open a referenced model as a top model by clicking the Open As Top Model icon on a Model block that references it.

Edit, Reply to, and Resolve Comments

In the Comments pane, pause on a committed comment to receive options to edit it, reply to it, resolve it, and show the block that corresponds to it. Clicking Show in Model highlights the block to facilitate finding the block in the block diagram.

When you pause on a resolved comment, you receive options to reopen the comment and to show the block that corresponds to the comment.

Hide and Delete Comments

To display fewer comments in the Comments pane, on the Review tab, clear Comment List > Show resolved comments. Alternatively, permanently delete all resolved comments by selecting Comment List > Delete all resolved comments.

When the comments file is on the MATLAB path, deleting a block that has comments also deletes the corresponding comments. If you undo the deletion of a block, the block and its comments are restored.