Linestyle mismatch

Does anyone know why this non WYSIWYG thing happens?

Here is what a part of a drawing looks like in SU:

And here is the same drawing imported into LO:

The dotted lines are part of a group representing a portal frame. As you can see, in LO the dotted line has overridden the solid line in SU. I can think of a workaround but I am interested in understanding why it happens.

So the dashed edge part of the frame and that frame sits behind the first rafter, which is solid? (behind, according to the camera…ie, the dashed lineshould be obscured from this view)?

AFAIK in sketchup it appears solid because that’s the edge which is in front of the other one (correct draw order), but in LO, is appears dashed because LO simply isn’t very good at figuring out where the camera is.

If the dashed line is in the exact same place as the first line, then I’m told that the draw order is based on how sketchup organises itself internally (bit like a model heirarchy).

So yeah, it happens because SKP and LO have different ways of ‘drawing’ what is in front (facing camera). It’s a LO bug, basically.

Question tho- if you wanted the dashed line to have a large thickness, would you still want it to appear behind the solid line?

How does autocad represent it if you export a 2d or 3d DWG?

It’s a 2D drawing in SU so there is no draw order and everything is on the same plane. But SU must “decide” which takes precedence.

It seems odd indeed if SU makes one decision on draw order and LO makes another! Still maybe that is indeed what is happening.

What I want is what I see in SU as that is the primary working platform. So I tend to take the view that if it looks right in SU it should look right in LO (wrong, huh?).

I don’t want to change linestyles or thicknesses, just the draw order. And I do know lots of ways to get what I want. But it’s a shame to need to.

Great comment. I tend to think this way as well. The only way I have found to address this is with stacked viewports…which in essence is me only caring about the general view of a scene in Sketchup and then overriding Layout’s decision about draw order.

Stacked viewports would be one option but what a faff! I tend to take the easier route of just hiding or deleting the offending line in SU.

What I suppose I mainly want to know is this. If you have two coplanar groups in SU, one with one linestyle and one with another, how does LO decide which to make dominant? Because there may be a way within SU of arranging things such that you get what you want without workarounds.

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Will be following to see if there is answer to that one…could save me a ton of time.

You would expect me to say this Simon… I’d draw this directly in Layout.

I don’t set dashes for tags in SketchUp. I do that for the viewport in LayOut. That makes it easier to show lines as dashed in one viewport while not dashed in other viewports if I want. Additionally, the appearance of the dashed lines in LayOut depend on the viewport’s Rendering type, viewport Line Scale (line weight) as well as the tag’s Line Scale settings. These are things you cannot control in SketchUp. The appearance I want also depends on the size of the viewport I’m displaying them in. On a large sheet with a large viewport I will want one setting for the dashed line scale and for a smaller sheet I’ll want a different one.

I’m guessing that the problem you are having with your dashed lines can be sorted out easily enough.

So does that mean you see no dashed lines in SU?

I can see how using stacked viewports gives you a lot of control in LO, but my kind of drawings would get a bit busy if I couldn’t see the dotted lines when I am working in SU.

It all seems a bit counterintuitive if you don’t see what you are going to get. In fact, I used the term WYSIWYG earlier because that always used to be a central tenet of computer programming.

But ultimately, you’re right. Lots of ways to skin the cat.

Yes. That’s what it means. I don’t need to manage a whole lot of different scenes in SketchUp that way.

Even without considering the dashes you don’t see in SketchUp what you are going to get with LayOut. As I said, what you get in LayOut depends on factors that are not shown or controllable in SketchUp.

Yep and some of them are easier and more predictable than others.

Can I ask this?

Could one do both? Set a tag for a dashed line in Sketchup so we can see how the drawings will be in Layout, but then in Layout not use that tag for presentation but instead your method of controlling line-weights and styles with the Layout viewport as you have suggested?

I’m not quite sure I see how that could work. Would you have a separate copies of the object each with a different tag with one shown as dashed and the other not?

If you really want to see the thing with dashes in SketchUp you could assign dashes to the tag in SU and remove the dashes or change them for the tag in LO.

My personal preference I guess but I find the dashes in SketchUp difficult to work with. They make the file look more cluttered than solid lines. Since we were given the ability to control dash style and lineweight by tag I’ve been able to greatly reduce the number of scenes I have to herd in SketchUp. I only need to have my one working style and model management is much easier. As I said before, I can make a single scene do multiple jobs in LO. For example for the various plan views of a building I only need one scene. I can show the roof plan, floor plan, foundation, footings, etc. all from that single scene.

So then the mindset is “model for drawings” instead of “model for the model”?

I don’t think so. I model for the model. I set up my scenes to use in LayOut for the drawings. I keep my model files streamlined so they are easier to work with when I have to make the inevitable edits and updates.