What is difference - Line Based vs. Face Based Families

[mmiles]

So, I think the different options for Generic Models is quite helpful, but I am not totally sure I understand the differences between some of them.

My assumption was I wanted a "Face" based family that I could use for trim (or batten) boards on my building. The generic family allows me to place this family on either a wall, or a mass (in my case) which gives me flexibility I need. However, the line based family type enables me to have greater control in the instance (length) parameter and placement than with a "face based" one. so, my workflow was this:


create face base family with multiple types of "width" parameters, and instance of length
load into line based family and place on the ref. level
align to centerline ref. planes, and ref. planes defining the ref. line (length)
link face based length parameter to line based family parameter.But, this seems redundant. Have I gained anything by inserting the face based family into the line based one? And, at this point, how can I make use of the various width parameters? I guess I am wondering if have I done more than necessary. Should I have just started with the line based family and ignored the face based family template?

thanks.

[Steve_Stafford]

Line Based = Two Pick placement
Face Based = Single Pick Placement - on a Face

Putting a line based family inside a face based "kills" the two pick concept. If you really need face based you'll need to just use that, strong reference planes and instance parameters assigned to dimensions and reference planes.

[twiceroadsfool]

As a rule, i dont put any Hosted elements inside other elements. I find they get quirky then.

I use Line Based for anything thats dictated linear in fashion: Dentil Moldings, Cornices that i cant handle with Wall Sweeps, Door Sills, and anything that needs to measure a linear distance.

Face based, i use for an Instance/Item that needs to be able to sit on a face, that may or may not be a wall/ceiling/roof/etc. I like to make a Face based version of things that are ceiling hosted, in case i end up using a curtain system for the ceiling (2x4 with removed panels), or if the ceiling is built in to the floor above, etc.

[mmiles]

Line Based = Two Pick placement
Face Based = Single Pick Placement - on a Face

Putting a line based family inside a face based "kills" the two pick concept. If you really need face based you'll need to just use that, strong reference planes and instance parameters assigned to dimensions and reference planes.

I am doing the opposite - placing a face based inside a line based. I want the two pick concept. (For some reason) I thought I saw a video whereby that was done. Yet, it seemed redundant to me.

The line based can be applied to a "face" or other workplane, right? what guidelines are there for where the geometry within the family is placed. for example, I know this particular geometry will be applied to a vertical face. My first thought was to draw geometry in elevation view, but when I went to place it in the project, the geometry was perpendicular to the face I selected. So, recreating the geometry on the ref plane (i.e. floor plan view) the geometry inserts the way I envisioned this originally - on the vertical face of my mass- but why are the relationships to views in the family (i.e. elevation) different than in the project environment?

[Steve_Stafford]

The "rub" is that there is no "face" in a Line Based family to act as the host face so methinks it won't work.

[Scott Womack]

Steve is right as usual. You cannot nest any type of hosted family, inside of a non-hosted family. Face Based, is a hosted family. Line-based is not. Thus never the two shall meet (and both function correctly). You can host a non-hosted family inside of a hosted one. However, when the line-based family is hosted inside of a, say, wall hosted family, the two point placement is lost.

[mmiles]

hmm....when I placed the Host based family into the line based family - it only required I set the workplane on which to place it. It did seem to work (although not like I intended it).

Mine was very simple extrusion, but like i mentioned, I placed (nested) in a family elevational view (Front) so during the placement in the project environment it was placed perpendicular to what I desired. That, in turn led me to revise the placement within the family editor, and then ultimately ask (and determine) that I did not need to make the hosted family in the first place.

Clearly, for my needs, this particular family is best made using line based family. I still am not sure why the placement of the geometry does not correspond to my project needs (i.e. placement of an element on a vertical surface would presume creation in elevational view, not plan view). At this point, I have what I need, but I was hoping to clarify how the family template worked. Hey, I cannot seem to locate anything in the help menu on generic family types - am I missing something? I am just perusing the table of contents, by the way.

thanks for your comments.

[twiceroadsfool]

The Views inside the Line Based Family are misleading. Almost everytime i built them, they were turned 90 degrees, until you get the hang of it. So to speak, the "Floor Plan" in the LBF is not a "Floor Plan" in the mode per se, but it is the "View" looking at the "Workplane" that the "Line" is drawn on.

For instance: I use them for Dentil Moldings a lot. The workplane i will draw the "Line" on in the project is the Cornice. If i was staring straight at the Cornice (id be looking at an elevation) i would see the faces of the Dentils. If i model it that way in the family, it works.

But if i consider that the LBF says "Floor Plan" and model my Dentils standing up, ill be laughing at myself and redoing them later. :)

Nesting hosted families is almost never a good idea.... Not even hosted inside hosted. Ive seen people nest wall hosted doors in to wall hosted doors, and invariably they get in to trouble, when they place the parent door somewhere that doesnt have a wall where the nested doors origin is. Then youre in trouble. But it will work in a few situations, which misleads people in to thinking theyre okay. If i need to nest a door family in a door family (panels, for instance) i start with an UNhosted Generic Model, change it to a Door, then load it in the wall hosted Door Family. Now it is a *door*, but the nested family doesnt have the quirks of the hosted element.

I heart Line Based Families.... But the Hardware doesnt, hahahaha...

[mmiles]

I think I've got the LBF figured out. I am training myself to disregard the "view" and think of it in terms of what/how do I want to see the family once I place it, and I model that on the ref plane.

As for nesting:
What about nesting a window into a door family? This seems like a common application to me - would you recommend against it?

[twiceroadsfool]

I Wouldnt nest a window built in the native window template, in to a door. But thats just my preference. When i nest windows in to windows, or windows in to doors, i use an UNhosted window, by starting from a generic model and using the method i described above. Change its catagory and put it in.

For what its worth, ALL of my doors and Windows are built that way. It makes family typing and content management much easier. The only caveat is (since theyre shared) that you have the *loose* doors and windows in the dropdown as well, but all you have to do is make sure people know not to place them, which is pretty obvious...

[t1.shep]

I'm trying to wrap my head around this, and if I get a response before I dive in to the family creator that's great....
I have an element that I need to create...we'll call it a vertical trim piece...
I want to use a line based family, and I want to be able to create it while in an elevation view...
So, in elevation, I want to click the bottom point of the trim and then the top point of the trim...
Can I do this with a Line Base Family?
If I read this post correctly, I need to ignore that the "plan view" is not necessarily the "floor plan" in the project...
So, if I draw my trim piece going from left to right in the family creator, I'm effectively drawing the "face of the trim piece"? And if I go to the Left or Right view in the family creator I'd be really looking at the plan view when I place it in the project?