topic Re: Set a size/shape for points when drawing with PrimitiveType.PointList in Revit API Forum

Set a size/shape for points when drawing with PrimitiveType.PointList

FRFR1426 — Mon, 10 Jun 2024 13:54:40 GMT

I've written a server derived from IDirectContext3DServer and use the primitive type PrimitiveType.PointList to draw positions. But the vertices drawn are only 1px wide, so it's hard to see and therefore useless.

Is there any way of increasing the size of the points and/or changing the shape drawn?

Re: Set a size/shape for points when drawing with PrimitiveType.PointList

Moustafa_K — Mon, 10 Jun 2024 14:06:17 GMT

I couldn't find a way to set this also, the thing i am currently using as a work around is ITemporaryGraphicsHandler

which i implement a custom image and render it over point location. this is an example.

I would also be glad to know of there is permanent solution for vertex shapes

Re: Set a size/shape for points when drawing with PrimitiveType.PointList

FRFR1426 — Mon, 10 Jun 2024 16:40:04 GMT

Nice hack. I thought it might be possible to draw a quad oriented towards the camera by retrieving the latter's direction with DrawContext.GetCamera(). But I need also to draw text so I think I will use a window with an Helix Toolkit viewport. This API is far too limited to be useful.

Re: Set a size/shape for points when drawing with PrimitiveType.PointList

ricaun — Mon, 10 Jun 2024 19:04:04 GMT

I would love to have the feature to set a width in the line, to make easier to visualize like the Thin Lines does.

In my case I experimenting to 'convert' to a mesh like a cube for the point and a extrusion for the line, is kinda expensive. 😐

The same thing for the text feature, if you convert the font to a mesh is possible to simulate a text in the DirectContext3D.

Still need to find a good polygon to mesh algorithm, at the moment I'm using the GeometryCreationUtilities.CreateExtrusionGeometry to create a solid, and getting the first face to show in the DirectContext3D. Works but have some Revit limitations.

Re: Set a size/shape for points when drawing with PrimitiveType.PointList

Moustafa_K — Mon, 10 Jun 2024 21:15:56 GMT

I was able to render most of the text using FormattedText.BuildGeometry. but like you said it has some limitation. The thing is that building geometry function does not give you enough data to render a text exactly as it looks. but it is some how acceptable. For example

the gray is the normal 3D Model Text by Revit

the Red is Direct 3D

Font used Ink free

zooming to see the differences

another function I tried is GraphicsPath

this function does indeed extract a very close match to font shape. but with extreme cost of faces and points. The thing that I think the buffer couldn't hold, and shown a broken geometry

gray is normal model Text

olive is using GraphicsPath

I still see the Formatted text has a better performance and some how acceptable effect... and the too precise match is not that required, at least for me. I will try to post a more analytics results by numbers, but time is too late for me now. 🙂

Re: Set a size/shape for points when drawing with PrimitiveType.PointList

ricaun — Mon, 10 Jun 2024 23:52:26 GMT

Never used this FormattedText, I'm using the WaterTrans.GlyphLoader package to get the content of the font.

Look's similar, at least I need to convert each segment to a path depending if is line, bezier or quadratic bezier.

In your case probably you are not creating multiple points when is a bezier segment, that's could be the reason your curve looks odd.

How are you doing to convert the PathGeometry to a polygon? And then create the 2d mesh to get each triangulate to render in Direct 3D?

Re: Set a size/shape for points when drawing with PrimitiveType.PointList

Moustafa_K — Tue, 11 Jun 2024 06:16:29 GMT

ok here are some numbers: I tested both functions with a single character 'T'

GraphicsPath Method Report
-------------------------
Text to Render: T
Total number of Points: 104
Total number of Curves: 35

FormattedText Method Report
-------------------------
Text to Render: T
Total number of Points: 47
Total number of Curves: 47

Line types are not extracted typically as the glyph drawn. Seems GraphicsPath has a better algorithm for tracing that.

I have attached the extracted line types

Red: Formatted Text

Blue: GraphicsPath

this is how dense the points are reflected over the shape

@ricaun wrote:
Never used this FormattedText, I'm using the WaterTrans.GlyphLoader package to get the content of the font.
Look's similar, at least I need to convert each segment to a path depending if is line, bezier or quadratic bezier.

I didn't know about waterTrans, I will have a look over it. In fact i do exactly as you do, checking and converting each line type depending on its type. the thing is curves that are expected to be bezier are returned as polyline segment

@ricaun wrote:

How are you doing to convert the PathGeometry to a polygon? And then create the 2d mesh to get each triangulate to render in Direct 3D?

yes, after creating curves, i create solid, then from solid to mesh. see this example

List<CurveLoop> rvtCurves = []; var formatted = fontSettings.GetFormattedText(message); GeometryGroup geo = formatted.BuildGeometry(new System.Windows.Point()) as GeometryGroup; var pathGeometry = geo.GetFlattenedPathGeometry(); foreach (var fig in pathGeometry.Figures) { var cloop = new CurveLoop(); XYZ startPoint = fig.StartPoint.ToRvtPoint(); for (int i = 0; i < fig.Segments.Count; i++) { PathSegment seg = fig.Segments[i]; try { Curve curve = null; if (seg is LineSegment lineSeg) { curve = Line.CreateBound(startPoint, lineSeg.Point.ToRvtPoint()); } else if (seg is BezierSegment bezSeg) { var p0 = startPoint; var p1 = bezSeg.Point1.ToRvtPoint(); var p2 = bezSeg.Point2.ToRvtPoint(); var p3 = bezSeg.Point3.ToRvtPoint(); curve = HermiteSpline.Create([p0, p1, p2, p3], false); } else if (seg is PolyLineSegment polSeg) { var points = polSeg.Points.Select(o => o.ToRvtPoint()).ToList(); points.Insert(0, startPoint); foreach (var item in points.DrawAPI(false)) { cloop.Append(item); } } else if (seg is PolyBezierSegment polBezSeg) { var points = polBezSeg.Points.Select(o => o.ToRvtPoint()).ToList(); points.Insert(0, startPoint); curve = HermiteSpline.Create(points, false); } else { // Unsupported type yet } if (curve != null) { cloop.Append(curve); startPoint = curve.GetEndPoint(1); } } catch (Exception ex) { // something went wrong } } rvtCurves.Add(cloop); } }

@ricaun wrote:
In your case probably you are not creating multiple points when is a bezier segment, that's could be the reason your curve looks odd.

yes I also though the same, but later i realized formattedtext function is behind all that, which led me to find out GraphicsPath

I am also summarizing with some additional inputs of my findings over here

Re: Set a size/shape for points when drawing with PrimitiveType.PointList

FRFR1426 — Tue, 11 Jun 2024 08:15:50 GMT

I think the way you create the Hermite spline from the Bézier spline is wrong:

var p0 = startPoint; var p1 = bezSeg.Point1.ToRvtPoint(); var p2 = bezSeg.Point2.ToRvtPoint(); var p3 = bezSeg.Point3.ToRvtPoint(); curve = HermiteSpline.Create([p0, p1, p2, p3], false);

HermiteSpline.Create Method (IList<(Of <(<'XYZ>)>)>, Boolean) creates a Hermite spline that interpolates the supplied points. The curve passes through all points. But a cubic Bézier curve only passes through the first and last points.

You should use the HermiteSpline.Create overload to specify the starting and ending tangents.

var tangents = new HermiteSplineTangents(); tangents.StartTangent = (p1 - p0).Normalize(); tangents.EndTangent = (p3 - p2).Normalize(); curve = HermiteSpline.Create([p0, p3], periodic: false, tangents);

Re: Set a size/shape for points when drawing with PrimitiveType.PointList

Moustafa_K — Tue, 11 Jun 2024 14:52:29 GMT

That will be a great level up, I will try it. Yep! the explanation of how Hermit is placed, makes sense now. Thanks @FRFR1426

Re: Set a size/shape for points when drawing with PrimitiveType.PointList

ricaun — Tue, 11 Jun 2024 15:04:56 GMT

Interesting, the method GetFlattenedPathGeometry already does the job to convert the bezier curves to PolyLineSegment.

In your sample you could just use the PolyLineSegment to create straight line.

If you add something like this you can control how many points in the bezier curves, lower tolerance more points.

var tolerance = 0.01; var pathGeometry = textGeometry.GetFlattenedPathGeometry(tolerance, ToleranceType.Absolute);

That's a really good and simple way to create a list of points that represent text shape.

I gonna use this approach to generate the points, now just need to find out a better way to convert the points to triangles without Revit.

I'm experimenting some algorithms to triangulate the points to a mesh in Godot.

Anyway I gonna create a video using the GetFlattenedPathGeometry with GeometryCreationUtilities.CreateExtrusionGeometry that is kinda simple to create and explain, and does not require external library.

Re: Set a size/shape for points when drawing with PrimitiveType.PointList

Moustafa_K — Tue, 11 Jun 2024 16:01:55 GMT

yep, exactly :), I like it to be honest, I was writing the below and then i realized you got it also, I have updated my blog accordingly. 🙂

Edit 11th June

I was able to realize the why FormattedText shows different optimized shape than GraphicsPath, due to the face we are using this statement

var pathGeometry = geo.GetFlattenedPathGeometry();

This statement accoriding to Documentation The polygonal approximation of the geometry. thus if we changed the tollerance of flattening, it would return a better result.

 var figures = geo.GetFlattenedPathGeometry(.00001, ToleranceType.Relative)
                  .Figures;

This is using FormattedText with flattengeometry of .00001 almost the maximum. which returned exactly what is expected

now we play with tolerance to suit the performance against quality as it is always every developer challenge 🙂

Re: Set a size/shape for points when drawing with PrimitiveType.PointList

Moustafa_K — Tue, 11 Jun 2024 16:16:25 GMT

I see significant benefits in using the FlattenGeometry algorithm. For instance, when importing CAD lines that contain many unnecessary points, we can create PathGeometry from these lines and then flatten it. This approach can also be particularly useful when working with topography subregions or outer boundaries.

This is a valuable takeaway for this week. thump up every one 👍

Re: Set a size/shape for points when drawing with PrimitiveType.PointList

ricaun — Tue, 11 Jun 2024 17:10:24 GMT

The default GetFlattenedPathGeometry without the tolerance gonna use the font size as base to add more points or not.

Only make sense to use tolerance if you need a small font with many points for some reason. And Revit has a limit when creating Line, really small line is not possible to create.

Makes more sense to create with a bigger font size and scale down the points to match a millimeter size.

Looks like 2.75 font is 600mm, when converting the Point to XYZ you could scale in there.

public static XYZ ToRevitXYZ(this System.Windows.Point point) { var factor = 2.75 / 600; return new XYZ(point.X, -point.Y, 0) * factor; }

And if you create a font with size 150 gonna create the XYZ points with the Height 150mm inside Revit.

Using a tolerance with the value 2 and this approach seen to result a readable font, kinda similar resolution with the shape Revit model Text does.

Re: Set a size/shape for points when drawing with PrimitiveType.PointList

Moustafa_K — Tue, 11 Jun 2024 17:15:33 GMT

I think it is not only related to big or small. it how much curvy it is... small font with less curves, then we may not need tolerance at all.

Re: Set a size/shape for points when drawing with PrimitiveType.PointList

Moustafa_K — Tue, 11 Jun 2024 17:33:44 GMT

forgot to mention... that when converting to solid, then we can have what the font size is rendered. because each font scales differently. thus, from the solid we can use Transform.ScaleBasis(value) in the direct context 3D, to scale it to the size we need saying intendedWidth should be 1 meter long

scale = intendedWidth/Solid.GetBoundingBox().Width; // extention function are helpful here

What do you think?

Re: Set a size/shape for points when drawing with PrimitiveType.PointList

ricaun — Tue, 11 Jun 2024 18:07:58 GMT

This is a 5mm font with GetFlattenedPathGeometry and the Revit Text model:

Revit kinda ignore the points near each other, would make sense to do the same thing with a temporary text.

Here is a room with walls to compare how small that font is.

The tolerance only control how many points gonna be generated in the bezier curve, is some kinda of distance showing in the doc. "The maximum bounds on the distance between points in the polygonal approximation of the geometry".

I have some implementation using scale for the solid, is kinda possible to force to generate a smaller line but I don't think that makes sense to generate a perfect temporary text really small inside Revit.

Re: Set a size/shape for points when drawing with PrimitiveType.PointList

Moustafa_K — Tue, 11 Jun 2024 18:14:09 GMT

Totally agree..., the only reason i came up with the idea of scaling is when i was rendering different dimensions to different sizes to study a furniture. which came in handy while studying.

I will try to think your way if i can find out what i need to make it more optimized which over all reflects over the performance

Re: Set a size/shape for points when drawing with PrimitiveType.PointList

ricaun — Tue, 11 Jun 2024 19:59:49 GMT

What font are you using?

You probably should use a more square font, that gonna generate less points and less triangles.

Here some samples:

The Arial have less polys in the '0123456789 abcdefghijklmnopqrstuvwxyz' sample.

Arial NumTriangles:719 Calibri NumTriangles:1580 Comic Sans MS NumTriangles:1118 Times New Roman NumTriangles:1064

This Geometry.GetFlattenedPathGeometry method is pretty fun.

Re: Set a size/shape for points when drawing with PrimitiveType.PointList

Moustafa_K — Tue, 11 Jun 2024 20:15:49 GMT

yeah the more straight lined font the better performance and quality indeed

Ink free font i am using

Re: Set a size/shape for points when drawing with PrimitiveType.PointList

ricaun — Sat, 15 Jun 2024 14:12:17 GMT

Just to finish this Text for DirectContext3D rabbit hole, here is my implementation using the FormattedText instead of the WaterTrans.GlyphLoader package that I was using. Thanks for sharing that approach @Moustafa_K.

The code only generate the basic shape, the DirectContext3D implementation is not included at the moment.

https://github.com/ricaun-io/RevitAddin.FontGeometry.Example