Another use for "Special Point Constraint" control
- Mark as New
- Bookmark
- Subscribe
- Mute
- Subscribe to RSS Feed
- Permalink
- Report Inappropriate Content
2005-03-09
06:03 AM
- last edited on
2023-05-23
05:22 PM
by
Rubia Torres
Use it to move an existing object (wall, line, toilet, etc.) a set distance away from another object. For a bad example: a toilet has been placed, and I want to move it...... so it's 18” from the centerline of the toilet, to the edge of the adjacent wall.
1. Select toilet.
2. Command D (Edit-Drag)
3. “D” (to activate “special point constraint”)
4. Select center point of toilet
5. Move pointer in direction of move.
6. Hit “R” & input distance (Shift before R if you want to “lock in angle”)
7. Return
8. Drag the cursor to the edge of wall.
Is there an easier to do the same? I used to drag “the object” to the “other object” and then drag it back away the necessary distance. This way I probably save 2.375 seconds out of my day, but I like that.

Red Canoe Architecture, P. A.
Mac OS 10.15.7 (Catalina) //// Mac OS 14.5 (Sonoma)
Processor: 3.6 GHz 8-Core Intel Core i9 //// Apple M2 Max
Memory: 48 GB 2667 MHz DDR4 //// 32 GB
Graphics: Radeon Pro 580X 8GB //// 12C CPU, 30C GPU
ArchiCAD 25 (5010 USA Full) //// ArchiCAD 27 (4030 USA Full)
- Mark as New
- Bookmark
- Subscribe
- Mute
- Subscribe to RSS Feed
- Permalink
- Report Inappropriate Content
2005-03-09 04:26 PM
Stress wrote:Should this be in the opposite direction that you want to move?
5. Move pointer in direction of move.
try this
1 select object
2 control d (drag)
3 select center point to drag from
4 move curser (holding shift) to wall edge you want to offset object off of
5 type R
6 input desired offset followed by +(plus) or -(minus)
7 hit return
- Mark as New
- Bookmark
- Subscribe
- Mute
- Subscribe to RSS Feed
- Permalink
- Report Inappropriate Content
2005-03-09 05:42 PM
Stress wrote:I might be missing something you've already said, but setting a custom origin point is the easiest way to move an object to a position relative to another object.
Use it to move an existing object (wall, line, toilet, etc.) a set distance away from another object. For a bad example: a toilet has been placed, and I want to move it...... so it's 18” from the centerline of the toilet, to the edge of the adjacent wall.
...
Is there an easier to do the same? I used to drag “the object” to the “other object” and then drag it back away the necessary distance.
You can pick up the object to be moved in the same way you suggested, but then move your pointer over the datum point and press shift-alt (Win) or shift-option (Mac). This repositions the origin point to whatever point you were snapped to, so you are free to place the object as if it had been on the datum point to start with. All the coordinate values (x/y/r/a) will all be relative to that point.
Central Innovation
- Mark as New
- Bookmark
- Subscribe
- Mute
- Subscribe to RSS Feed
- Permalink
- Report Inappropriate Content
2005-03-09 06:13 PM
You can pick up the object to be moved in the same way you suggested, but then move your pointer over the datum point and press shift-alt (Win) or shift-option (Mac). This repositions the origin point to whatever point you were snapped to, so you are free to place the object as if it had been on the datum point to start with. All the coordinate values (x/y/r/a) will all be relative to that point.Does this assume that the toilet (for discussion sake) is already in the correct position? How can you define a datum point 18" from the center line of the toilet (used in the example) if there is nothing to snap to already at that point? I must not understand your methodology or the use of the term "datum point". Thanks.
- Mark as New
- Bookmark
- Subscribe
- Mute
- Subscribe to RSS Feed
- Permalink
- Report Inappropriate Content
2005-03-09 06:43 PM
Mike wrote:The point about using the special point constraint to snap to the centre of the toilet is perfectly valid - I don't have anything to add to that.You can pick up the object to be moved in the same way you suggested, but then move your pointer over the datum point and press shift-alt (Win) or shift-option (Mac).Does this assume that the toilet (for discussion sake) is already in the correct position? How can you define a datum point 18" from the center line of the toilet (used in the example) if there is nothing to snap to already at that point?
However, I thought it help to point out that you can set the origin point anywhere you like while dragging an object in order to move it relative to that point. The original posting didn't mention this, so it might help.
You can set the origin onto any snap point by pressing shift-alt (Win) or shift-option (Mac). If you do this while dragging, you can then specify an x/y/r/a offset from that point, not the one you originally dragged from (see the illustration). In this case I could type y -18" (or snap along the wall and type r -18", etc)
Central Innovation
- Mark as New
- Bookmark
- Subscribe
- Mute
- Subscribe to RSS Feed
- Permalink
- Report Inappropriate Content
2005-03-09 07:01 PM

1. Make the circled node in the attached picture your placement node
2. get a check mark with your cursor in the corner where the arrow is
Let's say you want the center of the WC to be 18" from the horizontal wall and 6" from the vertical wall
3. type y 0-18+
4. type x 0-6-
5. type Enter (Return)
Done.
woodster
- Mark as New
- Bookmark
- Subscribe
- Mute
- Subscribe to RSS Feed
- Permalink
- Report Inappropriate Content
2005-03-09 07:03 PM
I thought it help to point out that you can set the origin point anywhere you like while dragging an object in order to move it relative to that point. The original posting didn't mention this, so it might help.Thanks for the clarification. Sometimes I am just a little slow

- Mark as New
- Bookmark
- Subscribe
- Mute
- Subscribe to RSS Feed
- Permalink
- Report Inappropriate Content
2005-03-09 07:11 PM
woodster wrote:I think the original post was for cases where the node you circled doesn't exist, i.e. a toilet symbol which doesn't have a hotspot in the centre. In that case, you can use the Special Point Constraint to project the centrepoint.
You guys are really making this wa-a-a-y too complicated![]()
1. Make the circled node in the attached picture your placement node
2. get a check mark in the corner where the arrow is
I was trying (perhaps not too well) to show how you do your second step - setting the 'check mark' or origin position - with a keypress.
Central Innovation
- Mark as New
- Bookmark
- Subscribe
- Mute
- Subscribe to RSS Feed
- Permalink
- Report Inappropriate Content
2005-03-09 07:23 PM
Ralph wrote:
I think the original post was for cases where the node you circled doesn't exist,
It was more a case of not knowing how to use the method Ralph and Woodster suggest. Like I said, I was dragging the toilet to the wall and then dragging it back 18". Thinking back "ArchiLink" showed me the coord. method, but it never sank in (til now). I started using SPC and it's become habit.
It is a different (maybe not better) way to use the tool.
Cheers,
Marc
Red Canoe Architecture, P. A.
Mac OS 10.15.7 (Catalina) //// Mac OS 14.5 (Sonoma)
Processor: 3.6 GHz 8-Core Intel Core i9 //// Apple M2 Max
Memory: 48 GB 2667 MHz DDR4 //// 32 GB
Graphics: Radeon Pro 580X 8GB //// 12C CPU, 30C GPU
ArchiCAD 25 (5010 USA Full) //// ArchiCAD 27 (4030 USA Full)
- Mark as New
- Bookmark
- Subscribe
- Mute
- Subscribe to RSS Feed
- Permalink
- Report Inappropriate Content
2005-03-09 08:49 PM
Stress wrote:But is it not easier to 'drag & drag back'? ...and faster. Keying in two sets of numbers is probably slower. But it is interesting as a teacher of archicad to see how different minds work!Ralph wrote:
I think the original post was for cases where the node you circled doesn't exist,
It was more a case of not knowing how to use the method Ralph and Woodster suggest. Like I said, I was dragging the toilet to the wall and then dragging it back 18". Thinking back "ArchiLink" showed me the coord. method, but it never sank in (til now). I started using SPC and it's become habit.,Marc