IfcGradient #550

SergejMuhic · 2023-03-11T14:39:05Z

Please treat as a basis for discussion. Do not review in detail. It is an idea. I do not even know whether the call of the function from IfcGradientCurve would work with this method signature.

pjanck

It seems that some local variables aren't properly defined. IfcGradient function should be revised.

...ce definition data schemas/Schemas/IfcGeometryResource/Functions/IfcFactorial/Expression.txt

...rce definition data schemas/Schemas/IfcGeometryResource/Functions/IfcGradient/Expression.txt

pjanck

Further improvements suggestions :) I generally agree with the overall architecture of the function.

...rce definition data schemas/Schemas/IfcGeometryResource/Functions/IfcGradient/Expression.txt

larswik · 2023-03-13T08:13:35Z

I may be a bit confused here but shouldn't it be Segment.ParentCurve?

larswik · 2023-03-13T08:49:07Z

What about .PARABOLICARC.? IfcPolynomialCurve?

SergejMuhic · 2023-03-13T16:09:38Z

What about .PARABOLICARC.? IfcPolynomialCurve?

Should be easy. Just need to derive the equations. I did not get to it.

pjanck

Further clarification questions.

pjanck · 2023-04-12T12:52:42Z

...rce definition data schemas/Schemas/IfcGeometryResource/Functions/IfcGradient/Expression.txt

+    NextSegment : IfcCurveSegment := GradientCurve.Segments[i + 1];
+    Location : IfcCartesianPoint := NextSegment\IfcCurveSegment.Placement\IfcAxis2Placement2D.Location\IfcCartesianPoint;
+    SegmentPlacement : IfcAxis2Placement2D := Segment.Placement\IfcAxis2Placement2D;
+    SegDistAlong : IfcParameterValue := SegmentPlacement.Location\IfcCartesianPoint.Coordinates[1];


It feels weird that the 1st element of IfcLengthMeasure array would be assigned to a IfcParameterValue. Should there be any conversion / length adjustments according to the dataset's units?

pjanck · 2023-04-12T12:53:18Z

...rce definition data schemas/Schemas/IfcGeometryResource/Functions/IfcGradient/Expression.txt

+  REPEAT i := 1 TO (SIZEOF(GradientCurve.Segments) - 1);
+    Segment : IfcCurveSegment := GradientCurve.Segments[i];
+    NextSegment : IfcCurveSegment := GradientCurve.Segments[i + 1];
+    Location : IfcCartesianPoint := NextSegment\IfcCurveSegment.Placement\IfcAxis2Placement2D.Location\IfcCartesianPoint;


Propose to call it NextLocation to clearly encode that it is the location of the next segment.

pjanck · 2023-04-12T12:54:52Z

...rce definition data schemas/Schemas/IfcGeometryResource/Functions/IfcGradient/Expression.txt

+    SegmentPlacement : IfcAxis2Placement2D := Segment.Placement\IfcAxis2Placement2D;
+    SegDistAlong : IfcParameterValue := SegmentPlacement.Location\IfcCartesianPoint.Coordinates[1];
+
+    IF (Location.Coordinates[1] > Position)


This comparison needs some attention. Currently it is comparing an IfcLengthMeasure with an IfcCurveMeasureSelect.

pjanck · 2023-04-12T13:01:01Z

...rce definition data schemas/Schemas/IfcGeometryResource/Functions/IfcGradient/Expression.txt

+        'IFCCLOTHOID' IN TYPEOF(Segment.ParentCurve) :
+          BEGIN			
+            RETURN SegmentPlacement.Location\IfcCartesianPoint.Coordinates[2] + 3 ** -1 * Segment.SegmentLength ** 3 + (3 * IfcFactorial(7)) ** -1 * Segment.SegmentLength ** 7 + (5 * IfcFactorial(11)) ** -1 * Segment.SegmentLength ** 11;
+          END;		


All other equations take into account (Position - SegDistAlong), but I cannot see this here. Is this intentional?

pjanck · 2023-04-12T13:02:27Z

...rce definition data schemas/Schemas/IfcGeometryResource/Functions/IfcGradient/Expression.txt

+
+        'IFCLINE' IN TYPEOF(Segment.ParentCurve) :
+          BEGIN
+            RETURN SegmentPlacement.Location\IfcCartesianPoint.Coordinates[2] + Segment.ParentCurve\IfcLine.Pnt[2] + Segment.ParentCurve\IfcLine.Dir.Orientation.DirectionRatios[2] * Segment.ParentCurve\IfcLine.Dir.Magnitude * Segment.ParentCurve\IfcLine.Dir.Orientation.DirectionRatios[2] * (Position - SegDistAlong) / Segment.ParentCurve\IfcLine.Dir.Orientation.DirectionRatios[1];


Mutliplication with Segment.ParentCurve\IfcLine.Dir.Orientation.DirectionRatios[2] happens twice. Intentional?

pjanck

Improvements suggestions to the documentation of IfcGradientCurve.

pjanck · 2023-05-04T08:13:03Z

...finition data schemas/Schemas/IfcGeometryResource/Entities/IfcGradientCurve/Documentation.md

@@ -1,3 +1,5 @@
 Gradient curve is a type of curve 3D curve representation that is based on its 2D projection (BaseCurve) and a height deifned by its gradient segments which can be derived from a function that retrieves it from the segment start height, its placement and the ParentCurve instance and the type of the ParentCurve.


Suggested change

Gradient curve is a type of curve 3D curve representation that is based on its 2D projection (BaseCurve) and a height deifned by its gradient segments which can be derived from a function that retrieves it from the segment start height, its placement and the ParentCurve instance and the type of the ParentCurve.

Gradient curve is a type of 3D curve representation that is based on its 2D projection (BaseCurve) and a height function (IfcGradient). The curve is defined on the curvilinear surface, with its first (horizontal) axis being the BaseCurve and the second (vertical) axis being perpendicular to the plane in which the BaseCurve lies.

I would put the sentence about the gradient function into the documentation of the IfcGradient function.

pjanck · 2023-05-04T08:17:41Z

...rce definition data schemas/Schemas/IfcGeometryResource/Functions/IfcGradient/Expression.txt

Documentation document is missing. Proposal for a first draft:

The IfcGradient function derives the height of any position (Position) along a IfcGradientCurve (GradientCurve). It iterates the gradient segments (GradientCurve.Segments) and retrieves the height from the segment's start height, segment's placement, and segment's ParentCurve instance and type.

SergejMuhic added 3 commits March 11, 2023 15:37

eof for two entities

8b1b34c

adding IfcFactorial

4d0a278

implementing IfcGradient

6fcc215

SergejMuhic added the EXPRESS Issues or pull requests relating to EXPRESS schema label Mar 11, 2023

SergejMuhic requested review from larswik and pjanck March 11, 2023 14:39

SergejMuhic self-assigned this Mar 11, 2023

pjanck requested changes Mar 11, 2023

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SergejMuhic added 4 commits March 11, 2023 18:19

forgot to delete

34a0654

deleting unwanted comment

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bad local definitions

177389e

NextSegment was accidentally removed

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pjanck requested changes Mar 11, 2023

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...rce definition data schemas/Schemas/IfcGeometryResource/Functions/IfcGradient/Expression.txt Show resolved Hide resolved

assuming last segment has zero length

7eb4849

pjanck requested changes Mar 12, 2023

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SergejMuhic added 6 commits March 12, 2023 16:41

reformatting exponentiation

454551c

defining SegDistAlong and Coorindates reference in Location

f19ce7a

using SegDistAlong

b80afa0

modifying line and curve ratios and indentation

bcbc77a

changing to normalized orthogonal derived P

90f8b86

slight update proposal

08fbcef

correcting Segment.ParentCurve attribute reference

4388822

pjanck added the Legacy Issues stemming from before 2023.01.01. label Mar 15, 2023

pjanck requested changes Apr 12, 2023

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pjanck requested changes May 4, 2023

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pjanck added the BucketA Content 4.3.2.0 or older label Mar 25, 2024

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IfcGradient #550

IfcGradient #550

SergejMuhic commented Mar 11, 2023 •

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		@@ -1,3 +1,5 @@
		Gradient curve is a type of curve 3D curve representation that is based on its 2D projection (BaseCurve) and a height deifned by its gradient segments which can be derived from a function that retrieves it from the segment start height, its placement and the ParentCurve instance and the type of the ParentCurve.

	Gradient curve is a type of curve 3D curve representation that is based on its 2D projection (BaseCurve) and a height deifned by its gradient segments which can be derived from a function that retrieves it from the segment start height, its placement and the ParentCurve instance and the type of the ParentCurve.
	Gradient curve is a type of 3D curve representation that is based on its 2D projection (BaseCurve) and a height function (IfcGradient). The curve is defined on the curvilinear surface, with its first (horizontal) axis being the BaseCurve and the second (vertical) axis being perpendicular to the plane in which the BaseCurve lies.

IfcGradient #550

Are you sure you want to change the base?

IfcGradient #550

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SergejMuhic commented Mar 11, 2023 • edited Loading

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SergejMuhic commented Mar 11, 2023 •

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