# Construction Geometry Extension

**URL:** <https://discourse.shapr3d.com/t/construction-geometry-extension/2105>\
**Category:** Modeling Questions\
**Created:** [February 23, 2018, 6:21pm UTC](https://discourse.shapr3d.com/t/construction-geometry-extension/2105 "2018-02-23T18:21:24Z")\
**Posts on this page:** 13\
**Page:** 1

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**Author:** ![tommyn](https://sea2.discourse-cdn.com/flex002/user_avatar/discourse.shapr3d.com/tommyn/32/1714_2.png) [@tommyn](https://discourse.shapr3d.com/u/tommyn)\
**Post date:** [February 23, 2018, 6:21pm UTC](https://discourse.shapr3d.com/t/construction-geometry-extension/2105/1 "2018-02-23T18:21:24Z")

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Construction Geometry, as implemented, helps out a lot but sometimes I want an axis to be longer or a plane to be bigger in its display. Geometry based on points allow size setting to some degree. Is there a trick to adjusting the displayed construction geometry? The easiest approach to extend an axis or plane?

Thanks for your support.

Tommy

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**Author:** ![DanielR](https://sea2.discourse-cdn.com/flex002/user_avatar/discourse.shapr3d.com/danielr/32/582_2.png) [@DanielR](https://discourse.shapr3d.com/u/DanielR)\
**Post date:** [February 23, 2018, 6:25pm UTC](https://discourse.shapr3d.com/t/construction-geometry-extension/2105/2 "2018-02-23T18:25:42Z")

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Hi Tommy - there is no way to do this. Would you submit an example of when it would be useful, would love to see one

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**Author:** ![tommyn](https://sea2.discourse-cdn.com/flex002/user_avatar/discourse.shapr3d.com/tommyn/32/1714_2.png) [@tommyn](https://discourse.shapr3d.com/u/tommyn)\
**Post date:** [February 23, 2018, 6:37pm UTC](https://discourse.shapr3d.com/t/construction-geometry-extension/2105/3 "2018-02-23T18:37:00Z")

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Ok; the next time I run across a case. Thanks

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**Author:** ![tommyn](https://sea2.discourse-cdn.com/flex002/user_avatar/discourse.shapr3d.com/tommyn/32/1714_2.png) [@tommyn](https://discourse.shapr3d.com/u/tommyn)\
**Post date:** [February 25, 2018, 8:26pm UTC](https://discourse.shapr3d.com/t/construction-geometry-extension/2105/4 "2018-02-25T20:26:30Z")

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Ok, here is a related example.

I want a construction line in 3D space. Nothing exotic, about 5 in. long, let’s say parallel to a main axis but elevated in z. On this line, I want to establish a number of perpendicular planes with each plane having a certain cross section centered on the construction line. This would the way one would loft an aircraft fuselage but in my case it is for a contoured knife handle.

So I extruded a cube and put a construction line on a top edge and set up a number of planes on this line.

![image](https://cdck-file-uploads-us1.s3.dualstack.us-west-2.amazonaws.com/flex002/uploads/shapr3d/original/2X/6/62ad41ab5542ccf6947b9dabfec62efc7b37a2a7.jpg)

The problem is when I 2x tap a plane to go ortho to draw a cross section, I cannot locate the line. I assumed your planes to be a fixed size so I drew the Big X to locate the line. But this is not very elegant.

![image](https://cdck-file-uploads-us1.s3.dualstack.us-west-2.amazonaws.com/flex002/uploads/shapr3d/original/2X/0/0042a92d9b0df5f7a9d46f147ff1ed0fc721c15b.jpg)

In any of intersection with the planes the line is a point. Any way to make this point visible in the plane ortho projection? This would be very helpful.

Thanks,

Tommy

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**Author:** ![tommyn](https://sea2.discourse-cdn.com/flex002/user_avatar/discourse.shapr3d.com/tommyn/32/1714_2.png) [@tommyn](https://discourse.shapr3d.com/u/tommyn)\
**Post date:** [March 4, 2018, 12:13am UTC](https://discourse.shapr3d.com/t/construction-geometry-extension/2105/5 "2018-03-04T00:13:54Z")

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![image](https://cdck-file-uploads-us1.s3.dualstack.us-west-2.amazonaws.com/flex002/uploads/shapr3d/original/2X/8/8cf573c27182f3f8d7f70854a8ee08c14cd0e616.jpg)

Here is a more obvious example:

I set up 4 planes using the 3 point method. Each plane uses two corners of the base sketch and a point elevated just above the X intersection of the base sketch. As you can see the plane in the foreground does not even include the bottom two points used to establish it. The side planes are ok but the front and back planes don’t even include their establishing points. (See named planes in Groups).

Thanks,

Tommy

s3d file encl.

[Construction Planes.shapr](https://cdck-file-uploads-us1.s3.dualstack.us-west-2.amazonaws.com/flex002/uploads/shapr3d/original/2X/1/162c7344d436388802fb6269664cde69947175db.shapr) (372 KB)

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**Author:** ![tommyn](https://sea2.discourse-cdn.com/flex002/user_avatar/discourse.shapr3d.com/tommyn/32/1714_2.png) [@tommyn](https://discourse.shapr3d.com/u/tommyn)\
**Post date:** [March 4, 2018, 1:18am UTC](https://discourse.shapr3d.com/t/construction-geometry-extension/2105/6 "2018-03-04T01:18:18Z")

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Another example:

![image](https://cdck-file-uploads-us1.s3.dualstack.us-west-2.amazonaws.com/flex002/uploads/shapr3d/original/2X/6/657e49027d8eb12a8d1ac0821a2af609811baf3f.jpg)

Created 2 planes at 45 deg angle on a square sketch. It seems that you can sketch off the displayed plane in ortho. The two lines that I drew on the XZ axis plane intersect. I drew a third line from a corner to this central point but it does not seem to establish a face?

Thanks,

Tommy

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**Author:** ![Istvan](https://sea2.discourse-cdn.com/flex002/user_avatar/discourse.shapr3d.com/istvan/32/23668_2.png) [@Istvan](https://discourse.shapr3d.com/u/Istvan)\
**Post date:** [March 4, 2018, 5:51pm UTC](https://discourse.shapr3d.com/t/construction-geometry-extension/2105/7 "2018-03-04T17:51:10Z")

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Because they are not created on the same sketch plane. Sketches only create fillings when they are on the same skethc plane. If you open the groups menu, under the sketches panel you will see 4 sketch planes: one for the rectangle, and three for the other 3 lines.

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**Author:** ![tommyn](https://sea2.discourse-cdn.com/flex002/user_avatar/discourse.shapr3d.com/tommyn/32/1714_2.png) [@tommyn](https://discourse.shapr3d.com/u/tommyn)\
**Post date:** [March 13, 2018, 12:42am UTC](https://discourse.shapr3d.com/t/construction-geometry-extension/2105/8 "2018-03-13T00:42:48Z")

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Going back to my original question, I now think that the info I received was not correct.

In the latest Helmet Tutorial video, around minute 3:00, the designer creates an Offset plane, then he Transforms it for some reason. Seeing this and some simple minded tests show that you can Transform the plane and make it more suitable to one’s situation.

In Istvan’s just prior response, yes l knew the lines were not on the same sketch plane — the issue is how to assure this — it seems by moving or transforming the plane? I never thought this to be possible and never tried it. I will experiment more.

BTW, these demo tutorials are excellent and much appreciated. They would be better if the demo person would always say What he was about to do and also Why it is being done. This is not always so obvious.

Thanks,

Tommy

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**Author:** ![Istvan](https://sea2.discourse-cdn.com/flex002/user_avatar/discourse.shapr3d.com/istvan/32/23668_2.png) [@Istvan](https://discourse.shapr3d.com/u/Istvan)\
**Post date:** [March 13, 2018, 11:37pm UTC](https://discourse.shapr3d.com/t/construction-geometry-extension/2105/9 "2018-03-13T23:37:37Z")

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Thanks for the feedback, I am really happy that you like the tutorial. More to come very soon!

Can you elaborate a bit on the sketch plane thing?

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**Author:** ![tommyn](https://sea2.discourse-cdn.com/flex002/user_avatar/discourse.shapr3d.com/tommyn/32/1714_2.png) [@tommyn](https://discourse.shapr3d.com/u/tommyn)\
**Post date:** [March 14, 2018, 12:27am UTC](https://discourse.shapr3d.com/t/construction-geometry-extension/2105/10 "2018-03-14T00:27:48Z")

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I watched Part 2 of the Bike Helmet tutorial today. This is also very well done. In this video, planes are clearly manipulated leading me to believe that I was unclear on the concept. I am going to re-do my edgy, space frame project with my new found realizations.

In the Bike Helmet demo, the designer often draws in a foreplane based on the photo, sketch or shape. His drawing skill results in an aesthetic addition. In my case, I tried to do the same thing but establish precise points and geometry — not always with success. I will advise how this goes.

Instead of rewatching tutorial videos or stopping and backing up, I have found that watching at 75% speed keeps the audio intelligible and makes it easier to understand the actions taken.

Thanks again for the tutorials. They are inspirational!

Best,

Tommy

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**Author:** ![tommyn](https://sea2.discourse-cdn.com/flex002/user_avatar/discourse.shapr3d.com/tommyn/32/1714_2.png) [@tommyn](https://discourse.shapr3d.com/u/tommyn)\
**Post date:** [March 18, 2018, 9:16pm UTC](https://discourse.shapr3d.com/t/construction-geometry-extension/2105/11 "2018-03-18T21:16:43Z")

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Let’s say you do a model something like this.

![image](https://cdck-file-uploads-us1.s3.dualstack.us-west-2.amazonaws.com/flex002/uploads/shapr3d/original/2X/c/c60b94628caf2a61aab15e0ca558d8db24b6ef79.jpg)

You draw the ‘faces’ by setting up a plane through 3 points. In many cases the plane is not drawn correctly, but is offset from the points. Let’s assume that the plane is drawn correctly through the 3 points. When you select the plane in ortho, usually 1 of the three points is not on the plane surface which is too small. So if you draw to this point, the line goes somewhere else.

So to practically do something like this, you have to first check if the plane is through the 3 points; if It is offset, Move it there using the Transform - Move/Rotate/Scale command and while you are there, Scale it larger so that it will contain your points when you go to plane ortho. It will always need to be Scaled. Thus you can draw the triangle in plane.

Hope that this helps someone.

Best,

Tommy

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**Author:** ![Istvan](https://sea2.discourse-cdn.com/flex002/user_avatar/discourse.shapr3d.com/istvan/32/23668_2.png) [@Istvan](https://discourse.shapr3d.com/u/Istvan)\
**Post date:** [March 19, 2018, 11:19am UTC](https://discourse.shapr3d.com/t/construction-geometry-extension/2105/12 "2018-03-19T11:19:26Z")

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Meanwhile we fixed a bunch of bugs in construction geometry, including this one. New release is coming in 2-3 days.

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**Author:** ![tommyn](https://sea2.discourse-cdn.com/flex002/user_avatar/discourse.shapr3d.com/tommyn/32/1714_2.png) [@tommyn](https://discourse.shapr3d.com/u/tommyn)\
**Post date:** [March 19, 2018, 9:37pm UTC](https://discourse.shapr3d.com/t/construction-geometry-extension/2105/13 "2018-03-19T21:37:47Z")

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Great news… You guys rock!

Tommy