Hi,
I’m using KiCAD 5.1.5, I’m not able to route the differential pair properly the way I wish I mean click and route. If you look at the DIFFPAIR image and when i try to change direction by clicking it just doesn’t allow me to ( as you can see in other two images - DIFFPAIR1&2)
Could you be a bit more specific? Explain what you expect to happen and compare it to what happens.
it’s a giant pain in the ass, the routing won’t happen if it decides the constraints can’t be satisfied. Try going off in different directions, or backtrack and take a slight different route.
Sometimes what works for me is to start from the other end. Also temporarily moving nearby components away.
It’s a serious issue in kicad as compared to other cad tools
If you look at the DIFFPAIR image and when i try to change direction by clicking it just doesn’t allow me to ( as you can see in other two images - DIFFPAIR1&2)
Check your net clearances. The grey area around your trace indicates the required clearance. It looks like it is set to a larger value than your diffpair separation. So either increase the diffpair separation or decrease the clearance (for the later make sure the fab can still produce your board if you decrease the clearance.)
General remark: KiCads interactive router does not really rely on you doing such micro management task as clicking to change direction. Click on the start point, move your mouse approximately along the route you want the trace to go and click on the endpoint.
If you want such fine-grained control then switch the router to highlight collision instead of walk around.
beg to differ. try routing a u turn without clicking.
that’s part of why it’s so annoying I guess… sometimes the right path is not a straight line. but if I try to make a 90 degree turn, for example, the routing stops unless I click it through the bend.
It is a bit hard to know what you mean from such a short post.
The picture i have of you is that you seem to dislike the automation that the interactive router brings (in general, build up over many posts of yours). This is ok. It is the reason why the highlight collision mode is there.
And to be honest the interactive router is not perfect. (Why else would there still be the section “improvements to the push and shove router” on the roadmap?) Especially on very long traces across the whole board. (Finding a true optimal path is after all NP complete so all we can do is find a good approximation. And approximations get worse the further you extend them.)
You are right a U-turn will require clicks. After all the interactive router searches for the shortest path. That is all it does. It takes your mouse movement as a suggestion but that is about the level of control you get. (This is on purpose. If you embrace the benefit of giving up control you will find that you can be incredibly productive using the semi-automatic router. In most cases way more productive than using a section by section router.)
I can think of four reasons why one would want a U turn. I don’t think i would revert to some manual routing for any of them:
- There is something in the way (the interactive router respects stuff that is in the way so here it would happily route around)
- Length matching (i would use the length matching tool as i would not want to do this manually)
- An antenna of some sort (A footprint is the better option here)
- Increased flexibility in some area of a flexible board (place a keepout zone where you want your traces to go around)
The interactive router does not place a straight line. It searches for the shortest path possible with all obstacles taken into account.
I would assume this complaint comes because the shortest path would result in the trace being somewhere where you want to leave space for something that comes later. If so let the router do its thing and then use the shove router to get the stuff through. (This will ensure that everything is still length optimized and you do not run the risk to leave too much or too little space.)
Do you mean a sharp 90° turn? You can deactivate the addition of a 45° section in the router settings.
Maybe this will make it clearer. Here I am just trying to exit the pads and move to the right. It requires several clicks to guide the router. Clearly there is a feasible path though, it seems pretty braindead that KiCAD can’t get from here to there.
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Also, it seems like the router prefers to hug existing objects (I suppose this minimizes waste of clearance). But that’s not my aesthetic preference, and sometimes leads to lovely solutions like this:
And of course in pretty much every situation I need to manually guide pad connections or get garbage like pictured.
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IIRC something like this has been reported and maybe even fixed for 5.1.6. You could try the test builds.
I just tried with the latest nightly and nothing seems different. Not too familiar with the development tree, would the fix be somewhere else?
Found one: https://gitlab.com/kicad/code/kicad/issues/1912. Not fixed. Comment there or give a thumb up if it looks like the same bug.
Not quite the same i would argue. That bug is when editing an existing diffpair.
It might be the case that solving one of the two issues solves the other one but i would still say a new report might be better. (gitlab has the “these bugs are related” feature so there are more options to have different but related bugs organized)
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