I sympathise with your frustration. Unfortunately, I cannot offer any specific advice to help with your issue, but I do agree with Horst that the model should not appear as it does in the preview and something is clearly wrong. The dual extruder separation distance is compensated for and S3D should preview the object exactly how it will print. If you can correct that, you might find your issue solves itself. CompoundCarl has said that it works correctly for him, so the software at least appears capable of doing it right.
If it does turn out that you're doing something wrong, don't feel bad about it because the documentation for this software is appalling. I have never paid so much money for such poorly documented software and I am very disappointed with it in that regard. Even the free alternatives seem to have much better documentation but they all have other shortcomings.
I am experiencing the same issue. It is super frustrating. It looks like moves between ooze shields are not retracting. Just bought this software and this is kind of a deal breaker. Please fix ASAP.
Basically what I am doing is using a script to cool the inactive nozzle to 165 and using the square in the corner as a wipe. I vertical lift set to 3mm and it works every travel move EXCEPT when the nozzle moves from one ooze shield to another. The retraction problem isn't an issue if the nozzle doesn't ever run across the part. In the file with no purge square, every layer has a travel move with no hop that runs directly into the model. In the factory file with the purge square, the travel moves that dont hop are all between ooze shields.
I imagine if S3D looked in its code for generating ooze shields and prime pillars it would find a bug that did not retract when moving from one ooze element to another.
tldr; There are two different processes created by the dual extrusion wizard and changing one doesn't always change the other. Rerunning the dual extrusion wizard with the template again and checking the settings to make sure they are as expected for both print processes fixed my problems.
I have been struggling with similar issues for several days now and the changes I've been making to my process to try and fix the stringing just haven't seemed to be making any material difference. I had a breakthrough on it this afternoon and wanted to share in case it helps out.
When I ran the dual extrusion wizard in the first place, I based it off one of my single extrusion profiles that has been working fairly well. When I had problems with oozing and stringing (specifically between the ooze shield and the main part), I started trying to adjust the settings in the process without rerunning the dual extrusion wizard. What I didn't realize was that the dual extrusion wizard had created two processes (one for each extruder) and I was only changing one of the processes and the other one ended up with a totally different set of settings.
I've played with it a bit since then and I'm not sure what the exact steps are to get the configuration mismatched between the two processes but I've managed to do it several times. Sometimes, it seems to apply the changes in one process automatically to the other but there's some set of steps that allows it to get totally out of sync. I think it has something to do with selecting a different profile in the drop down in one of the processes and then trying to change it back but I'm not totally sure.
In terms of a fix, the most reliable method I've found so far is to make the changes to the profile in the process, update it (or save as new), delete the processes and the process group, and then rerun the dual extrusion wizard with the revised profile set as the template.
I think I've managed to solve most of my stringing issues now. The setting that seemed to be key to fixing the stringing between the ooze shield and the main body was turning off "Only retract when crossing open spaces" in the Advanced tab. Not sure if it matters, but my ooze shield is also currently has two outlines.
The problem is not from the ooze shield, but from the prime pillar. In my case with my IDEX printer (BCN3D Sigma) I don't neet ooze shield, but I have the same issue between the prime pillar and my part !
If we check "only retract when crossing open space" there is no retraction between the pillar and the part. And that true, if we uncheck this option, the problem is solved. But we have another problem ! There are a lot of useless retraction !!
So please S3D developer, before to translate into muche more languages, start to considering the gap between the pillar and the part as an empty space !!!
I think there is a similar issue with printing any additions. I noticed that there are no retractions when there are multiple brims for a single piece. Notice that this only happens at the base between brims.