Dimension in a block record does not show on drawing

[JorenPelfrene]

See below example where the generated dwg-file shows the line, but not the dimension annotation. Is it possible to have a Dimension entity be part of a block record? It only seems to show on the drawing if added to the CadDocument.Entities directly.

CadDocument doc = new CadDocument();
doc.Header.Version = ACadVersion.AC1032;
doc.Header.ShowModelSpace = true;

BlockRecord block = new BlockRecord("block1");

ACadSharp.Entities.Line line = new ACadSharp.Entities.Line
{
    StartPoint = new CSMath.XYZ(1, 0, 0),
    EndPoint = new CSMath.XYZ(5, 5, 0)
};

DimensionLinear dim = new DimensionLinear() 
{
    FirstPoint = line.StartPoint,
    SecondPoint = line.EndPoint,
    DefinitionPoint = new XYZ(0, -1, 0)
};

block.Entities.Add(line);
block.Entities.Add(dim);


doc.BlockRecords.Add(block);
Insert blockinsert = new Insert(block)
    {
        InsertPoint = new XYZ(10,10, 0)
    };
doc.Entities.Add(blockinsert);

using (DwgWriter writer = new DwgWriter("C:/temp/acadsharp_trial.dwg", doc))
{
    writer.Write();
}

[DomCR]

Hi @JorenPelfrene,

This seems a limitation of the current version, when the dimensions are placed in the *model_space the blocks that draw the dimension are automatically generated, but if they are in a block, they don't appear because it doesn't generate the block.

I'll open a branch to solve this issue.

Thanks for the report!

[mme1950]

Hi @DomCR,
I spent some time to solve the problem that Dimensions created or cloned by ACadSharp do not show in AutoCAD.

Let me summarize the results of my investigations regarding the visibility of dimensions:

Scenarios
(1) Create a simple DWG with a Dimension in model space in AutoCAD, open and save (no modification) in ACadSharp.
--> The dimension is invisble in when the document is opened in AutoCAD.
(2) Use a DWG document containing a block with a dimension, clone the block into a new document.
--> The dimension is invisble in when the document is opened in AutoCAD, other content in the block is visible.
(3) Create dimension in ACadSharp
--> The dimension is visible in AutoCAD

My preliminary solution is:
When I compose a cocument Dimensions are created without a anonymous block in model space. Dimensions contained in blocks are cloned into model space and the anonymous-block reference is set to null.

• A dimension created in ACadSharp in the model space (without an anonymous block) is visible on AutoCAD.
• A dimension cloned from an other DWG into a new document created in ACadSharp in the model space is invisible in AutoCAD unless the reference to the anonynmous block is set null.
• Dimensions created or cloned in ACadSharp in a block with or without anonymous block are invisible in ACadSharp.
• AutoCAD creates missing anonymous blocks for all dimensions when the document is saved.
• Dimensions that are invisible in AutoCAD can be "repaired": open and save the block. All entities in the block including the dimensions with a new anonymous block created new.
• Dimensions created in AutoCAD seem always to be associated with an anonymous Block.
• The Dimension.XDictionary property sometimes points to a Dictionary with one entry AcDbContextDataManager pointing to another dictionary ACDB_ANNOTATIONSCALES with one entry pointing to an ACDB_ALDIMOBJECTCONTEXTDATA_CLASS object ("*A1") that cannot be resolved. This looks similar to the MultiLeader problem, that could be fixed by supporting the ACDB_MLEADEROBJECTCONTEXTDATA_CLASS.

Is it possible that the anonymous block needs an extra registration in the document - not only in the BlockRecords dicttionary?

[DomCR]

Hi @mme1950,

Sorry for the delay, on my end here is the result of the investigation:

(1) Create a simple DWG with a Dimension in model space in AutoCAD, open and save (no modification) in ACadSharp.
--> The dimension is invisble in when the document is opened in AutoCAD.

I've tested this on my end and the dimensions on appear on the model space of the new file, which version are you working with?

(2) Use a DWG document containing a block with a dimension, clone the block into a new document.
--> The dimension is invisble in when the document is opened in AutoCAD, other content in the block is visible.

Same here, I think this is fix if the block is cloned along the dimension, I can open a quick PR to fix it, I think you already post this solution?

The Dimension.XDictionary property sometimes points to a Dictionary with one entry AcDbContextDataManager pointing to another dictionary ACDB_ANNOTATIONSCALES with one entry pointing to an ACDB_ALDIMOBJECTCONTEXTDATA_CLASS object ("*A1") that cannot be resolved. This looks similar to the MultiLeader problem, that could be fixed by supporting the ACDB_MLEADEROBJECTCONTEXTDATA_CLASS.

I haven't found this record on any document, I guess that is what's causing the issue for the invisible blocks.
ACDB_ALDIMOBJECTCONTEXTDATA_CLASS this class has "AL" before the "DIM" which may stand for Alternative, I've noticed that dimension have "two" forms, that may be why this record exists.

Is it possible that the anonymous block needs an extra registration in the document - not only in the BlockRecords dicttionary?

I don't think so, in this PR #559 I've been playing with the dimension blocks, it works fine, even you can create a block that is just a circle or copy another block, when the dimension is modified it will refresh the block in Autocad and the old block will be replaced.

The solution that I'm proposing is that the user can decide if the blocks are updated by Autocad or by ACadSharp, but to do that we need to setup a lot of stuff, currently I'm finishing the text part for this issue, after that I think I would be able to work on the geometry if I'm not missing anything.

[mme1950]

Sorry for the delay,
Thanks for your great work, you may also have some other work to do ...

Which version
This is a good question. I used a special version with several fixes.
I should switch to the newest version of ACadShap when you merged your Dimension...-branch and retest.

*A1-Object
I saw this Block linked to a Dimension object in only one case, also in DXF. I could not find out which properties the ACDB_ALDIMOBJECTCONTEXTDATA_CLASS has. It did not appea in the other cases described below.
Lets forget this case for now.

[mme1950]

In #673 I proposed some changes to properly clone the anonymous block.
I am using these changes in my version. However, it did not solve my problem.
I think #673 overlaps with #559.
In my application I currently add the created and cloned dimensions in model space with a null reference to the Block property. This works and there is currently no urgency.
So I can wait until #559 is merged. I would be happy to help with information if needed.

[DomCR]

In #673 I proposed some changes to properly clone the anonymous block.

We can keep the writer part, I posted a comment on the second part regarding the anonymous blocks, what you think about the proposed solution?

I think #673 overlaps with #559.

No problem is a minor change.