part snap to grid

[DrPR]

I have inherited a PCB design for Ultiboard. NONE of the parts or traces are aligned with the visible grid. Nothing on the entire board seems to be aligned with the grid.

I need to place components so they are aligned with existing traces, but when I move parts they do not snap to the grid. It is essentially impossible to get anything to align correctly.

In "PCB Properties" "Grids & units" the design units are "mil" and the Part grid Grid step value is 5.00000. However, when I drag a part it will stop at any position between grid lines, and not at 5 mil increments.

How do I align the grid with existing traces?

How do I get components to shap to the grid? I have spent hours reading through the Ultiboard User Manual and I can find nothing about how to make components and traces snap to a grid.

Phil

[_user32]

DrPR,

There are actually several grids for Ultiboard, go to Options -> PCB Properties... Grid & units (tab)

Note there is the visible grid...  You can set this to match the other grids or choose it to be a setting that is coarser or finer than the other grids.  

On the drop down (shown above) there are other grids.   Most important are the Copper and Part grid.    You can adjust these separately.   The other thing to keep in mind - what is the object actually snapping to?   In the case of copper, the center of the routed copper traces will snap to the grid.   In the case of parts, it is usually the (0,0) setting of the part (which can be different in some parts, but is either 1 of 2 locations (usually), either A) the center of TH pin/SMT pad 1 or B) the centroid of the part (which is the official IPC landpattern standard except for connectors and other irregular shaped objects).   Most surface mount (SMT) parts will be defined as B) but you will find many through hole (TH) parts aligned to pin 1.

Also, if the 'snap to grid' isn't working for you (or its not "behaving" like you'd want), but instead you can accept aligning edges of parts at specified locations, Ultiboard does have some nice alignment tools (Edit -> Align).   In this case you select the parts you'd like to align to and align them in this fashion... you can then Group them together and nudge them as singular object.

As a last option, you can activate ruler bars (click on the border of the layout drawing where it looks like a ruler and an arrow will appear.  You can then drag parts on top of this ruler area (trick is the center needs to align to the ruler line indicator) and the part will 'snap' to the ruler and will allow you to align parts in this fashion...   You can drag the ruler and the parts will move with the ruler bar(s).

Regards,

Pat N

[DrPR]

Thanks.

Now I have another problem - how do you select a part by it's "handle?" I am trying to move a surface mount part, and it has a blue square with an "X" through it at the center of the outline. But when I try to move the part it is not selected by the handle, but at some random location where the cursor is pointing. When I try to position the part so the center is at an exact position I cannot. I cannot select the part at the center (handle), and the part always "drops" with the "X" off of the SMD grid.

This is making it impossible to align the part with existing traces. Instead of the selection point being on the part grid it is offset by a fraction of a mil, so when I try to place the part it will be positioned incorrectly by some number of ten thousandths of a mil. I have to say this is the most screwed up part placement I have seen in any program!

Explanation: The original board layout was done by a rank amateur who clearly had very little board layout experience. Apparently he changed grid centers and grid spacing multiple times during the layout, so some SMD parts are aligned to one grid and other parts are aligned to other grids. Traces seem to be aligned to multiple grids also. It is a total mess! I just need to replace a few parts, many with the exact same footprint and pinout. When I forward annnotated from the schematic these parts were placed outside the board outline. The existing trace pattern is on the board, so I just need to move the new parts to the same trace pattern.

Do parts have a selection handle? If so, how do I select a part by the handle? If I drag the part what grid will it snap to - the visible grid, the SMD grid, or no grid at all (where the cursor moves to)?

One more question. When I move a part slightly the program rips up all the traces associated with it, and after a minute or so it replaces the original traces with a horibly scrambled totally worthless autorouted mess with vias scattered everywhere! How do I defeat this assinine rerouting of perfectly good traces?

Phil

[Tien_P]

Hi Phil,

When you click on a part, you should see a dot indicating the part reference point and the reference point should snap to the part grid. If you are having difficulty align your part, reduce the part grid under Edit>>Properties>>Grid and Units, select "Part grid" and reduce the "Grid step value:"

When you move a part, the autorouter will re-route that part and the traces path will likely be different than previously.  If you prefer to reroute the part yourself, select Options>>Global Preferences>>PCB Design, uncheck "Re-route after move".