Adaptive-Family based Geometry: Discrepancy after placement

[Anonymous]

Hi there,

I have created a geometry using the Adaptive Family Template, the purpose of which is to construct a triangle, in which a cord is drawn in a way that it keeps its length always 6m and simultaneously parallel it the triangle's opposite side.

The model works perfectly when flexed, however, when it is placed on a Mass Model's surface it behaves in a different way as in the Family Model itself.

Do you have an idea of what the problem could be?

Geometry after placement onto a mass model's faceParametersAdaptive point settingGeometry shown inside the family file

[Anonymous]

Attached you find the file

[RDAOU]

@waelajam 

The way the family is now, there isn't much you could do about it unless you remodel the whole thing. As it is, the chord length is parametric driven by 2 instance parameters and not adaptive with respect to the placement points.

The way you have modeled it, the chord length is controlled by the normalized curve parameter(Pos_L & Pos_R) of the 2 points hosted on the reference lines (Side_L and Side_R)...for that ratio to adapt properly in the project environment, the 2 parameters Base_Length_L and Base_Length_R should in principle be reporting parameters and NOT input parameters.

If you want to work with it as is, you need to input the Base_Length_L and Base_Length_R manually in the project

See below screencast.

[RDAOU]

I have posted a detailed explanation why that is not working with a screencast but for the same odd reason the forum deleted it … @Discussion_Admin / Moderator notified...hopefully they will retrieve it from the recycle bin

[Anonymous]

Hi,

I could read your reply through the notification email I 've received.

It is not possible to set both the [Base_Length_L] and [Base_Length_R] as reporting parameters because Revit rejects using them in a formula. In addition, the Normalized Curve Parameter's value of the point placed onto the triangle's base cannot be read off and consequently transmitted to a formula.

What would you suggest?

[FAIR59]

you are overcomplicating the problem

• make a reporting parameter for the base length (total)
• define cord length with formula: cord = if(Base_Length < 6000 mm, Base_Length, 6000 mm) , cord length can't be larger then base length.
• the ratio from the top is : cord / base (see picture), so ratio from bottom :  1 - ( cord / base) 
• 
• apply ratio to both points of cord.

[RDAOU]

@waelajam 

Sorry for the late reply, I was in a meeting.

The current Base_Length_L & R cannot be set as reporting because you have used them in a formula already and that middle point on the edge is not a Host. Do the following:

1. Select that point and change it to a Shape Handle,
2. then change the Base_Length_L and R  reporting. 
3. Your family should work as is

[Anonymous]

Thanks.

It is based on the same concept of Similarity of Triangles, however,  so simplified that it undermines the whole concept. This geometry is apart of a system.

[Anonymous]

By do doing so, you 've unattached the point from the triangle's base. 🙄

Anyway, thanks.  Seemingly, I need to reconsider another construction method.

[RDAOU]

@Anonymous 

Practically, no not really...The base chord would be a Spline through the 2 adaptive placement points and the shape handle...Considering it is a Truss, one would assume that it will be hosted on a single plane; hence, all 3 points on the base chord will be coplanar => it will behave similar to a hosted point on a line segment be a straight line/chord. However, that point will not be aligned with the Triangle's altitude. 

I am not sure what you need that point on the base for...you didn't clarify in the OP. But if you do for some structural reason to be aligned with the altitude, then you would need to remodel as mentioned in my earlier post. 

[Discussion_Admin]

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@RDAOU wrote:

I have posted a detailed explanation why that is not working with a screencast but for the same odd reason the forum deleted it … @Discussion_Admin / Moderator notified...hopefully they will retrieve it from the recycle bin

---

This should be returned now

DA

[FAIR59]

you can calculate the values for Base_Length_L and Base_Length_R:

• add reporting parameter for Base_Length .
• Base_Length_L = (Base_Length ^ 2 + Side_Length_L ^ 2 - Side_Length_R ^ 2) / (2 * Base_Length)
• Base_Length_R = Base_Length - Base_Length_L

[ToanDN]

I was getting a headache trying to figuring out the gymnastic of formula that you show, then I tried another approach and it seems to be achieving the same goals.

[Anonymous]

Thanks.

Please do't try to make new siggestion.

I am trxing another geometry appeoach with Revit API.

Thank you all.