This article starts by looking at the reasons for merging any type of online help and then covers the detail of how to create merged help projects using Adobe RoboHelp 8. The article focusses on the production of merged WebHelp, but the technique described herein can be used with the FlashHelp, WebHelp Pro and FlashHelp Pro formats. Note that both WebHelp Pro and FlashHelp Pro need to be run on a server with RoboServer installed, also there is another method of creating merged help for the Pro versions. I have included a small section covering merged Microsoft HTML help (CHMs).
While written for RoboHelp HTML 8, this method works for all versions back to RoboHelp HTML X3, which was the first version enabling merged WebHelp to be produced without server support.
Note: RoboHelp for Word is not designed to produce merged WebHelp. There is nonetheless a method described on my site.
In order to make the most of this article, you need the following software and files:
Note: For best results, ensure that all available patches for your version of RoboHelp have been applied. They can be obtained from /support/robohelp/downloads.html
Sample files are available for RoboHelp HTML 7 and RoboHelp HTML 8.
To follow this article, you should understand how to create RoboHelp projects and edit project source files.
First, what is merged help? It is simply the output from a number of Adobe RoboHelp projects merged so that, to the user, it is no different than the output from a single project. The Table of Contents in Figure 1 is from merged WebHelp. How can you tell? You cannot—that's the point!
The first image is a combination of the Tables Of Contents from a number of projects. Then two of them are shown separately. As you can see, in the merged TOC, the books are exactly the same as from the individual projects.

Figure 1. Tables of contents from multiple projects are merged with results transparent to the user.
It's the same with the index, the search and the glossary. You can also create links between topics in different projects.
Merged help comprises the outputs from a parent and any number of child projects (master and subprojects, if you prefer). The beauty of merged help is that you can supply all or any of the outputs from the child projects. When the parent opens, it looks to see which children it can see; the parent and those children are then presented as one integrated help system. It is seamless to the user.
There are three key reasons for using merged help:
You might want to produce different outputs for many reasons. For example:
You simply generate all the outputs and then install just what you want the customer to see. Obviously, you have to be careful with cross-project links if you do not deliver all the outputs.
This is the key reason I started using merged help. When I joined the company I work for, they were producing WebHelp using RoboHelp for Word with all the content in one document. After clicking to open the project, we didn't go off to make the coffee, we went off to make it and drink it! Opening took around twenty minutes. With about 10,000 topics at that time and all of them in one document, that was hardly surprising. It was also risky.
The first thing I did was persuade management that RoboHelp HTML with separate topics was much safer, and more logical given that our output was WebHelp. It still took a little while to open the single project, but it was nothing compared to what it had been. Then along came RoboHelp X3, which was the first version to enable merged WebHelp to be produced without needing RoboServer (or RoboEngine as it was then). I took a copy of the project and trashed half the content to see what difference it made to opening, and it proved to be worthwhile. A look at the content indicated that I would end up with two projects of around four thousand topics each, plus a number of smaller projects. That was a level that made a noticeable difference when opening and working with the project, so I decided to try it. It was quite an effort splitting the content out into separate projects, as there were many links between topics that were going to be in separate projects. However, some careful find-and-replace operations dealt with changing the paths for the links.
Our customers get all the outputs and have never been aware of the change. Combined with the next reason, it was a decision I have never regretted.
Coming up to a new release, it can be necessary for more than one author to be working on the help. With a single project, that is not possible unless source control is in use. Because merged help comprises a number of projects, it is possible for us to work on different areas.
We each take a copy of all the projects, but any one person only works on the projects to which he or she has been specifically assigned. By having all the projects, they can create cross-project links. When the work is done, I bring it all back together. Quite simply, if Author 1 has worked on Projects 1 and 2, I delete the old versions from my master copy of the setup and copy in the new versions. From Author 2, I will take Projects 3 and 4. Then I generate the new outputs and deliver them to development.
You have to be very methodical and take backups, but it really is that simple. Now we will look at how merged help is created.
The method I'm demonstrating in this article was devised to overcome a little hurdle that had been set up by the way RoboHelp worked in an earlier version. That problem was fixed in Adobe RoboHelp 7; but the method has other advantages, so I still recommend it. While the screens will be different, the method works in all versions from X3 onwards.
The feedback that I have had tells me that this is regarded as the simplest method around. I use it for a merge involving some 12,000 topics in over 700 folders, so it is also robust!
When you create links between topics in a single project, the relative path between those topics will remain unchanged in the output, as otherwise they would not work. The same has to be true when creating merged help. The folder structure of the generated and published files is:
Parent Project
The same structure is needed for your source projects so that you can create links between them. While you can have content in your parent project, it is much simpler if all content is contained in the child projects so that the parent is effectively nothing more than a shell.
Before you read too much further, you need to consider how you want the TOC to be structured.
As with other forms of merged help, one project must be designated as the parent. There's nothing, though, to say that the user has to see the parent project! When merged WebHelp is opened by running the start page, what you normally see is shown Figure 2.

Figure 2. The conventional way of viewing merged WebHelp.
What my method does is open the help via the parent project, as it must, but then immediately switch to one of the child projects. So what the user sees is shown in Figure 3:

Figure 3. With this method, the user sees a topic from one of the child projects, rather than the parent.
From then on, all the content is in child projects, making the creation of cross-project links simpler. How that is done is described in the following sections.
ZIP files containing working examples for RoboHelp 7 and 8 can be downloaded (see the links at the beginning of this article). I have set all the file dates and times to be the same. This will enable you to identify any files you change. The ZIP file must be extracted to retain the folder structure. When you open the projects, you will see a warning about external links, just click OK.
As always, before you start using a new method on your live projects, do back them up first.
So that you can set things up easily when working on the source files, you need the folder structure shown in Figure 4 for your projects.

Figure 4. Use this model structure for your merged help projects.
In this model, you put all the topics that would be regarded as parent project topics in the child_1 project. The parent project in this setup contains only one topic that the user will never see. When the help is opened by calling the start page of the parent project, what happens is that the toolbar and navigation pane display, then the default topic for the parent project starts to open but a redirect in it calls the default topic for child_1. That is what the user sees.
I hope you have grasped the principles involved but don't worry if you haven't. Just continue on and it will become clearer.
Create a structure for the source projects similar to the one shown in Figure 4. You can call the folders whatever you want. I simply use "parent" and "projects" so that alphabetically, the order is the parent first and then the children.
First, create the main child project, which is simply a child project containing what would otherwise have been in the parent project. Typically, this will be an introduction to the product, how to use the help, and other such topics. The default topic for this project is the one you will later set up to be the "default" for the merged help. This project is created in its own folder within the projects folder.
Next, create any other child projects you require. These are also created in their own folders within the projects folder.
To create the links:
When creating links between projects, you may get a warning about links to external files. That is normal, and I have selected the "Do not display again" option. Note, however, that you cannot reverse that option anywhere, except by reinstalling RoboHelp!

Figure 5. "Link to" is where you create links. You may see the warning shown.
Note re Unix
When you publish a single WebHelp project with the "Use Lowercase Filenames" option selected, RoboHelp changes both the filenames and any links to lowercase.
When you publish each project in a merged help setup with the "Use Lowercase Filenames" option selected, RoboHelp will change all the filenames to lowercase, but links to files will only be changed to lowercase if the link is to a file in the project you are publishing. So, all the filenames will be lowercase, but some of the links will still be mixed case. This mismatch causes broken links on a Unix box.
You must ensure the case is the same for the files and links in your output. I ensure that all file names are lowercase from the start.
This mismatch is not an issue on Windows systems.
The next step is to create the references to the child projects and add the redirect in the only topic in this project. Reopen the parent project.
The parent project has no TOC as such, but this is where you tell the parent what children it has! Here we follow the RoboHelp instructions for including the TOC from the child project(s).
Click the Insert Merged Project icon (highlighted blue in Figure 6)

Figure 6. Clicking the Insert Merged Project icon brings up this dialog box.
Navigate to the XPJ file for the child and click Open.

Figure 7. Select a child project from the Open dialog box.
Repeat steps 1–3 until all the child projects are shown in the TOC as shown in Figure 8. The order of the references is the order in which their TOCs will appear in the merged help.

Figure 8. The child projects shown in the parent project's TOC.
Previously I have recommended using a meta tag as below to redirect from the parent topic to Child 1 with a 0 second delay.
<meta http-equiv="refresh" content="0;URL=./mergedProjects/child_1/child_1_topic.htm" />
Changes made in Firefox 3.0.9 mean that the TOC will not display using a zero delay. Changing the value to 1 second as below allows the TOC to display
<meta http-equiv="refresh" content="1;URL=./mergedProjects/child_1/child_1_topic.htm" />
but it will not synchronise until after the user has clicked some topics and that is not really satisfactory. Fortunately a quick look at some javasript sites found a script that, with a few changes, provides an alternative method that allows the TOC to both display and synchronise. It also works in Internet Explorer.
</head> tag. In your project you will need to amend the path to point to the topic in Child 1 that you want to be the default.
<script language="JavaScript" type="text/javascript">//<![CDATA[
<!--Script courtesy of http://www.web-source.net - Your Guide to Professional Web Site Design and Development //-->
var time = null
function move() {
window.location = './mergedProjects/child_1/child_1_topic.htm'
}
//]]></script>
<body onload="timer=setTimeout('move()',100)">
It is important that the topic to which the user will be redirected and the parent topic have the same colored background. If the two topics have different colors, the redirect may be detected.
You can generate to the !SSL! folder within your parent project, but I recommend that you generate to a folder outside the project; it avoids a lot of confusion and some problems that regularly crop up on the forums. In the download project, I have set things up to generate to a folder called generate. You can name it whatever you prefer.
You do not have to publish each time you generate and you can skip step 6 in this section for now if you wish. I will explain more about publishing later.
Start the Single Source Layout for WebHelp so that you see the first page of the wizard. By default it will appear as in Figure 9.

Figure 9. Page 1 of the Single Source Layout for WebHelp.
Change the Output folder and filename. The folder I have selected is outside the project folders. It's cleaner that way, with source in one folder and output quite separate. The start page file name will be projectname.htm by default. I prefer to rename it as index.htm. That is a standard name for a website and one familiar to your developers. It helps them identify the start page. Notice that I have not selected Use Lowercase File Names (see Figure 10). As already explained, that does not work across a merge, so if you want lowercase filenames, set them up that way rather than using this method.

Figure 10. Leave Use Lowercase File Names unchecked.
The last page of the wizard is where you set up publishing. Not everyone needs to publish. If you are not sure, see Step 11: Delivery. If you do need to publish, click New and enter the required location in the New Destination dialog box (see Figure 11). The name can be whatever you want.

Figure 11. The Publishing dialog box.
When you generated the parent project, it will have created a structure like the one in Figure 12, except the child project folders will be empty at this stage.

Figure 12. Generating the parent project produces this folder structure.
Follow the same steps as for generating and publishing the parent, except that you point to the appropriate child folder; for example, C:\rh8\generate\mergedProjects\child_1. Don't forget you also need to check the browse sequence options for the relevant child projects.
In the above example, you will see that the "P" in mergedProjects is uppercase. I recommend that you do not change this. Sometimes developers will insist on all lowercase paths and filenames, and if you encounter this you should explain that the capital "P" is forced by RoboHelp and that the workarounds risk breaking the help. If this is not accepted, then see my website for further information.
Provided you select Automatically in the Synchronize TOC option, once the help has been opened, the topics displayed will synchronize with the TOC. However, when you open the help, you may find the first topic displayed does not synchronize, particularly with larger projects. Thanks to Jose Badeau, there is now a fix if you encounter this problem.
You need to edit a file called whthost.js. You will find this in both the generated output and the published output. You only need to tweak the file in the published output unless you supply the generated output to the developers.
Open the whthost.js file in a text editor. Find the function realPutData().
The end of the function will look like this:
checkFillStub(); }
Edit it to look like this:
checkFillStub(); // fix to force sync top[1].frames[0].frames[0].syncWithShow(); }
That forces the TOC to synchronize every time, including when you open the help. If you use the generated output, you will need to make that change every time you generate. If you use the published output, in limited testing the change seems to stick, but it would be advisable to check for it each time you publish.
RoboHelp does not check external links, which includes links between the child projects, so you may want to consider a website link-checking utility.
Go to either your rh8_publish folder (or rh8_generate if you skipped publishing) and double-click the start page; index.htm, if you followed my example. Watch very carefully: what happens is that the default topic does open but immediately redirects to the default topic for child_1. You will probably not even notice it. If you want to test that, apply a bright red background to the parent default topic, then you will see it! That is also why I suggested giving this blank topic the same color background as the "default" topic to help mask its transitory appearance.
The parent default topic cannot be accessed, as there is no TOC for the parent project, you did not index that topic, and there is no text the search engine can find.
There it is: merged WebHelp with easily created links—all ready for delivery.
There will be differences between the dates and times of the generated files and the published files, as generating always creates new files, whereas publishing will only create new files if you select to republish all or if the file content has changed.
This means that if you elect to update the server outside of RoboHelp, you will not be able to easily identify what has changed in the generated folder, because all the files will be new, even though only some have changed. RoboHelp's publishing process, however, can track what has changed, so it knows what needs to be updated on the server.
Take a copy of the full merged WebHelp output and delete from the copy the folders for the projects that are not to be installed. It really is that simple. Take a copy of rh_generate from the download, delete the folder for Child 3, and then open the help. You will see that the TOC no longer shows the book for that project and the index no longer shows its topics. Also, any links from topics to the deleted child will break. You need to consider that in your design. In some cases, it may mean you do need to generate a new output after removing those links from the source.
Earlier in this article, I deliberately skipped over many of the fields in the wizard. I wanted you to focus on getting a project up and running. I hope you have now reached the stage where we can look a bit more closely at the various features available and expand on what you need to know. This section will also be useful if you are familiar with merging and just want to learn a bit more about doing so with RoboHelp 8.
Starting with the first page of the wizard (see Figure 13), I'll note the features and offer recommendations:

Figure 13. The first page of the wizard sets many of the key parameters for your project.
The next page of the wizard (see Figure 14) covers toolbar buttons, navigation options, and other settings.

Figure 14. Set toolbar buttons, navigation and additional options in the second page of the wizard.
The third page of the wizard (see Figure 15) offers navigation pane and speed optimization options.

Figure 15. Set options for the Navigation pane and speed optimization on the third page of the wizard.
The final page of the wizard (see Figure 16) covers publishing options.

Figure 16. Set your publishing location and related options on the final page of the wizard.
So what is different with merged Microsoft HTML help?
Avoid the use of underscores, the hash symbol and suchlike in the names of the CHM files you create. They have been found to cause problems with merged Microsoft HTML help. Stick with alphanumeric characters and no spaces.
You do not need the redirect topic described in Step 5 above, indeed you must not use that topic for this type of help. You will need a parent with at least one topic that is seen by the end user.
I still recommend you generate the CHM files to a folder outside of any of the projects; the generate folder, in my example. In the first page of the wizard, make sure you generate the output from all the projects into that one folder or the merge will not work.
After you have generated each CHM file to this folder, open the parent project and click the HTML tab shown in Figure 6 and browse to the folder where the CHM file was generated and select each CHM file in turn. When prompted, click Yes and allow the CHM file to be imported.
If you are using RoboHelp 7 or later and have to create both types of merged help, you can have more than one TOC; so you could create one for the WebHelp layout and one for the Microsoft HTML help.
Finally, generate the parent project to the generate folder. If you open that CHM file, you should see your merged project. The merge is set up, and links can now be created between the projects.
The links between topics in different projects are created in a different way, which is bad news if you have to create both merged WebHelp and merged Microsoft HTML help. If you need to output both types of help, you will have to create both types of link and then apply conditional build tags.
To create cross-project links, you need to have your default layout set to Microsoft HTML help. Then, when you click the Link To field in Figure 5. you will see an additional option, Remote Topic. When you select that, you will be asked if you want to import the target CHM file into the source project; you must select Yes. Choosing the topic to which you want to link is straightforward.
If you do not pause to get your mind around this part of these instructions, you could become confused later in the development of your help when you want to create more links:
Now, you want to create another link to a topic in one of the other projects; to which CHM file do you navigate?
Right now that may sound very confusing, but once you have created a few links, you will find it much easier.
You supply the parent CHM file always and whichever child projects you want the user to have. You take the copies from the generate folder, and they must always be in the same folder on the user's PC. If a CHM file is not in that folder, it will not appear in the TOC, its index entries will not display, and the topics will not be found by the search.
Once you have worked through setting up the merge and how it hangs together, you will soon realize that it is a very straightforward process; it is just a bit different from working on a single project. Calling the help will also require some changes, so make sure you liaise with your developers before changing things. If they have not factored in the time to deal with their side of things, you might not be flavor of the month! There is more information about merged WebHelp and about calling it on my site.
Peter Grainge is an Adobe Community Expert providing support through the Adobe hosted forum for RoboHelp and through his popular website, www.grainge.org, which contains many tips and best practices. He is based in the United Kingdom, where he works as a full time documentation manager controlling various online help projects and managing user documentation.