Whats New in TheoLt 8.22

Updates for Core:

  • Support for GstarCAD in Core Module
  • Expanded feature design including “step and repeat”
  • Front, Back, Left or Right side alignment for default orientations (elevations).
  • Settings File backups.
  • Updated Manuals

Updates for Building Survey:

  • Expansion of the BricsCAD tool set.
  • Support for “step and repeat” inserts in features.
  • Selection of just Text, Icon or both in Feature Folders (Plan Builder)
  • Flip inserted features in 4 directions (aleviating the need to always choose the same point for insert).
  • Updated Manuals

Are you aware of the “Pro” version? This includes;

  • Full Least Squares network adjustment (traverse)
  • Instrument motor control
  • Contouring

Request a trial now.

Elevation Views in AutoCAD

One of the most frequently asked questions by TheoLt users is:

‘How do I get an elevation view of the building I’m measuring?’

TheoLt sends 3D data to AutoCAD which is plotted in the lines and layers of your choice. It is useful to be able to vew the drawing as a façade. One method to achieve this is to use AutoCAD’s UCS (User Co-ordinate System) command to set up a façade UCS and view it square on. The 2 key commands are ‘UCS’ and ‘PLAN’. This example is a job started in WCS:

1. Place a polyline across the plan by snapping to the ends of a measured line (because this will guarantee the UCS will be true level) It’s the red line across the facade here:

2. Fix a UCS to the polyline. Use the UCS ‘e’ option (for ‘entity’ or ‘ob’ for object in late versions) to pick the polyline when prompted. Use ‘Plan’ to get a plan view of the new UCS.

3. Rotate the UCS about the required axis by 90 deg to point the Z axis at the viewer of the façade. This is done by entering ‘UCS’ on the command line and then the axis of roatation (x, y or z) then the angle, the default is 90deg. Watch the UCS icon to see what is happening.

4. Use ‘plan’ to get a plan view of the new UCS

5. (optional) Use UCSICON command to set ‘Noorigin’ to get the icon out of the way..

6.Save the UCSwith an apropriate name (‘Front’ ‘Back’ North ‘Elavation’ etc)  with the ‘S’ option at the UCS command for future use.

Enjoy your facade view!

TheoLt will plot lines true to the instrument orientation in AutoCAD regardless of the UCS. View-ports in model space can be used to run plan and elevation drawings at the same time. The façade UCS is also useful when setting up views of the 3D data for elevation drawings.

You can also use the AutoCAD ‘View’ command to save views too as a short cut to getting back to a view you like. Once the façade view is as desired it can be named for future use.

Tip: I find it helps to use your hand in the same way as we did to learn Flemmings Left hand rule (assuming you have your mouse in your right hand!)  in physics at school to work out the required axis of rotation at 3:

This is a useful method of setting up a facade UCS if your job isn’t aligned to the WCS : don’t forget TheoLt’s Default Orienation option to orient aligned with a plane which is great for quick starts aligned to a facade.

Traversing with Historic Scotland


Historic Scotland are investing in survey! As part of their development of a minimum site record we do a training exercise in travserse control. I am asked to trouble-shoot their field kit, update to TheoLtr8.1.6 and take 3 teams through network observation and adjustment. The practice site is Blackness Castle and the weather is cold but, mercifully, dry.

We rattle through setting up, do a 4 stn loop, make a mess of station naming, recover and head off to the paraffin perfumed barrack block to check the results. We work through our data and run the calc, the results are superb! The network is adjusted and applied and we enjoy a good buffet lunch before tackling 3 networks in 3 teams.

The new station name editing feature has improved using user defined station names at capture. The great thing about netadjust in TheoLt is the real-time aspect, poor shots are flagged as measured and preview calculations and diagrams can be run, all on live data. Traversing is all about procedure and adapting to new ways of working can make simple things difficult, it always takes patience to get procedures right and we have to make a few re-starts before we get the sequence to suit the situation.

Taking out the ‘brown’ data is a good starting point for analsing the network.

Taking out the poor shots, running the calc and seeing the result can prompt you to take more obs or, in this case,  shave 10ths of a mil off an adjusted station position: a far cry from the days of Bowditch and the calculator!

Because TheoLt works with live station properties station names have been on a like- it -or- lump- it basis until release 8 when it bemame possible to use a custon station name. This is a surprisingly useful improvment as there occasions when station names are pre-set from existing survey or when station ocupation is in decending order, in the past renaming was only possible as an AutoCAD edit post-survey, now the name can be set at Default Orientation or when the station is set out.

Customisable station naming is one method of working with pre-declared station identities, station names can now be determined at setting out adding a new level flexibility to  control operations.

This relatively simple addition to the functionality of Netadjust in TheoLt 8 has a great impact on workflow. Whether you are occupying existing control, adding stations to an existing network or creating a new network from scratch, Theolt now affords the Surveyor the optimum realtime platform for Control networks.

TheoLt Real-Time Network Adjustment offers a new workflow whereby the network benefits from:

  • Review of each observation- Interactive rejection of observations with real-time results update
  • The ability to ensure each station is complete before moving
  • Computation of Resections with multiple face oberservations.
  • Adjustment of CAD drawings to network- Live diagram in CAD

So before you put your kit back in the box you can be sure your network is delivering what you need!

A record survey by PhoToPlan

Drainage problems with the pavement on the gun deck of Martello Tower 24  this tower required a full record of the historic paving prior to lifting for English Heritage.

This is a rectified montage of the gun deck pavement and firing step of a Martello tower. It was achieved by 4m PAP (Pole Aerial Photography) in a single day on site. The pavement  level is  a stitch of 9 images, the firing step  12. The images were rectified in PhoToPlan and then balanced and feathered in Photoshop.

Control for the rectification was by REDM to detail points collected in TheoLt:

In this plan I plotted the wall top from intersection in PhoToPlan 3D, orientated to the same control points from our reconaisance KAP imagery:

This tower is impressively armed with a mighty 24pdr; we had to wait until it was lifted before we could record the pavement condition in advance of works to stop the leaking, visit when it rains and you get wet!

Once the pole is set up and the rig hoisted it’s a case of working as quickly as possible to get even illumination across the whole photo block…and taking advantage of rare moments of excitement like the bit where we have to negotiate the flag pole.

For completeness the pavement survey was required to cover the firing step so the images are rectified again but this time to the firing step plane. The control points are snapped onto the joint lines from the TST survey by TheoLt. 12 images got me around the ring.

I had hoped there would be a deep enough chord of the circle covered in each shot to make use of the minimum number of points I measured to describe the jointing of the circumference rail support blocks, this turned out to be the case but more points would have been better, some of the projected images came out a bit stretched!

Next the central pivot column is rectified so that the final montage is presented to a consistent scale:

The pivot post is easy: 6 points and its done! Bringing the pieces together completes the cover:

The 3 planes are combined into one single orthographic projection, there was a great deal of fitting needed to get the coverage of the pavement right up to the base of the central pivot post from oblique imagery taken with the pole on the firing step.

Re-inserting the montage back into AutoCAD and checking by PhoToPlan rectification showed a 9mm average discrepancy between the montage and the control points.

This documentation project is a great example of what can be done with PhoToPlan, Photoshop, AutoCAD TheoLt and….

…a camera on a stick!…

So in 4 easy steps we got from ‘no cover’ to ‘ortho’ cover.

TheoContour: Fast Contouring made easy!

You can spend a lot of money on contouring, the software tools for surface interpolation and depiction do not come cheap and even the ‘inbuilt’ AutoDesk options require a hefty investment in a ‘Map 3D’ or ‘Civil’ variant. But there is a very effective and low cost option which I have been using for some time now and it’s proved itself to be a good ‘fast and dirty’ fix for getting contours done: TheoContour.

Like all of the Latimer CAD family of tools this is based on the premise of solving a CAD problem, not a surveying one: there are no data tables to code, no CoGo computations to step over and the outputs are pure CAD entities ready for your next DWG based task. And of course all is in 3D from the start.

Let’s start by looking at the results:

This composite view gives you an idea of what TheContour is capable of: annotated smooth 3D ploylines and shaded surface generation.

So how does it work?

TheoContour is an arx/brx application:

it works with points so getting started is easy: just get your points into AutoCAD! The points can be layered anyway you choose, and obviously, they need to be congruent in terms of height consistency ( in other words they have to be organised such that the Z values are correct!)

Once we are happy all the points are in the current view in WCS the 1st TheoContour command is : theocollate which loads up the points and reports on the surface they describe ready for the next step:

I kid you not, the arx processes this stuff pretty quickly 2,703 points in about 3 s!

Note that the command line report relays the settings we are using on this model. They can be changed easily; I’m not happy with contours at 4 to the metre indexed on the metre so I go to settings and switch the index interval to 5:

I’m now ready to contour:

The command is, you guessed it: theoContour! Plotting the contours takes a little time, this example takes about 45s to generate. Some models can take a while, it’s all dependent on how fine the contours are combined the entity type being generated (lines, polylines or splined polylines).

Not bad for a 1st pass, I would return to the settings and look at smoothing but this gives you a good idea of how simple the process is: and it’s flexible- in effect the datum is the zero value for Z in the current UCS so you can use theocontour to generate contoured surfaces indexed to any plane defined by a UCS! The contours are 2D ploylines in 3D space so they can be edited easily using PEDIT to get them tidy!

So just using 2 commands and tweaking the settings I have got working contours in minutes.

TheoContour also generates profiles and shaded surfaces, the text annotation is pretty neat too but for now I just want to show how simple contouring CAN be if you use TheoContour!

TheoContour for BricsCAD

TheoContour can be downloaded as part of TheoLt core at:…

http://www.theolt.com/web/theo-contour/

TheoLt: Powerful Flexible Features.

One of the great advantages of TheoLt compared to other survey software is it’s complete flexibility.  For example, lets take a look at the “Features Library”.

The basic premise of TheoLt is that it transfers the measurement information or point from a survey instrument (or Distance Meter) to CAD to be used by any command  (for example, draw lines, insert blocks etc). What the TheoLt Features Library enables is for a series of measurements to be combined to insert a series of lines, arcs or attributed blocks (much like standard survey “feature coding”).

The feature definitions are accessed through the the settings dialog in the main TheoLt window. Definitions are grouped into folders.

Looking at it’s simplest use, inserting a single attributed block as a detail point. The first stage is to name the feature , define it’s icon and the number of measurements that should be taken to insert the feature. In this case, a single 3D measurement.

The next stage is to define any user attributes that may be required and whether confirmation is required (asking the user to confirm the values). Finally select the block to be inserted.

Once defined, opening the features panel will show the newly created item and a single click on the apropraite icon in the feature  palette will prompt for the measurement and the block will be inserted.

Next we can look at a more complex but typical use; kerbs tops and bottom in topographic survey. The aim here is to pick points on the top and the bottom of the kerbs, connecting the points, inserting blocks and annotating levels. This is very typical of topographic survey. Our definition will be point on top of kerb, point on bottom of kerb before moving on to the next part of the kerb.

Defining the feature, we name it and use 2 3D measurements with correct prompts. As we wish to join the points with lines, we will select “repeat insert” and join points on Layer (each point type having it’s own layer). This will allow the lines to be continued for as many measurements as required before exiting the command.  The attributes will be the Z-level of the first point only and two blocks will be inserted, each on it’s own layer.

Now when selecting the feature from the palate, the measurements are prompted, blocks are inserted and then the first prompt starts again. After the next round of observations, lines are drawn between the respective points on their designated layers. Options allow the lines to be curved, straight  and the alignment of the annotation to be altered or disabled.

The final example is a single complex item; a tree. To measure one fully quite a few measurements are required; the centre of the main trunk, the girth of the trunk, horizontal extent of the canopy and finally the vertical extent (height). These can be defined in the first window with prompts and measurement types. I would assume that for the first measurement the operator would take the angle to the centre of the trunk before taking the distance to the centre. This would leave the instrument pointing to the extent of the girth which we can collect as an angle only measurement. We can also choose to write the details out to a file which can contain any of the collected data fields for processing.

Next we will create the attributes where we will also collect the tree type which will be stored in a list to speed up the user input.

Finally we insert a block to represent the trunk – scaled to match the girth. A second block will be inserted, scaled to math the canopy.  An attributed block is inserted to hold the details of the tree (in addition to the file written above).

Obviously, this is not an in-depth analysis of what is possible from the features palate but I hope it gives some indication of the power within TheoLt.

TheoLt PRO: Traversing

These days big traverses are becoming a rarity. The GPS active net is doing a better job for many survey projects. Traversing is still the best way for getting good control for small sites, setting out, architectural photogrammetry and building survey. I remember the happy time at field school in Wales with booking sheet and pencil, baking in the summer sun, each station in turn becoming a kind of holiday home as we carefully logged back-sight and foresight obs. We got to live outdoors and enjoy it. So, given that this is the backbone of my work, why do I hate it so much?

It is the inevitable disappointment when, at computation, I discover the blunders! All the wonderful effort of getting stations set out, carrying forward heights, multiple obs is lost when the numbers don’t come out! Each time I set out to traverse I have the optimism of a child on a trip to the seaside only to face the bitter disappointment of having to repeat the work to get it right. This is something I have grown used to: traversing is a game of errors and I have, over the years, found out how to get the results I want. In truth I have never been happy with simply surveying for numbers, for me I want to see a drawing, detail, I want that map to grow, to make my mental map real; a schedule of co-ordinates to me is no thing of beauty. So what to do about it?

I can’t do my job without control; I’ll never forget the wise words of Peter Waldhausl when I asked him the teacher’s question: ‘what is the single most important thing to teach in survey?’  his answer, without hesitation, was very clear: ‘NO ACTION WITHOUT CONTROL!’

It’s thrilling to drive in the first peg on un-surveyed territory, this is without doubt part of the elemental appeal of surveying (it’s certainly is NOT the money…few of us are well paid and even fewer of us manage to keep our jobs!) we are part of making the unknown known in a very real way. Anxieties about control can be helped by getting the right tools and first and foremost in these tools is software! I use real-time software that tells me where I’m going wrong when I make the mistakes. Now I know this is not proof against blunder but it definitely helps! Keeping track of where the errors are is one thing but I’m amazed at how much gets in the way of your best rehearsed procedures when you are traversing: for crying out loud there are only 4 things to do:

1. Log the instrument and target heights of collimation (HoC).

2. Achieve and verify orientation.

3. Observe and book shots to back-sight & fore-sight.

4. Set out new station as required.

So what goes wrong?

Plenty! You forget which station you are at and use the wrong station ID, you set out a station then find the sight-line blocked, somebody ( it’s never you!) kicks a tripod and you have to re-set the HoC and retake the station orientation, you select the wrong HoC for the orientation shots, you forget to take the last angle in the loop because you think you already have the shot done as you have ‘been here before’ not to mention the lost marks, last minute datum changes, miss-matched tribrachs, ‘helpful’ people moving setups before they are measured, it starts raining etc.

The software definitely helps, I have a strong tendency to argue with it but I’m learning to trust it (yes I’m pretty stubborn like that I’m afraid).  The Netadjust tool in TheoLt Pro is what keeps my traverses on the straight and narrow.

It has some really good ‘idiot proof’ features which this idiot has learnt to adopt as procedural reinforcement:

Real-time feedback of station selection at occupation and orientation. I get a ‘heads up’ message on completing an orientation that advises me of the staion IDs, the HoCs and the precision of the orientation.

Automatic prompting of HoCs. Every time I take shot to a target I get a prompt, I can turn this off, but this is my most common foul up, its very difficult to ‘unpick’ HoC errors even though it is usually very easy to see where they occur.

Traffic light coloured observation results. This really is the best bit for me, TheoLt will let you know how good your shots are as you take them, you can drop the ‘bad’ obs from the computation, re-shoot or go right back and re-do the orientation again.

Automatic target ID. When you shoot a target with a known position you are prompted with its ID, a simple hint saving a mountain of time searching through tables to find a station ID.

Live diagram. I can preview my loop in AutoCAD/BricsCAD at any time; if it don’t look right it ain’t right. The diagram tells the story.

Non destructive back-up of raw data.  You can run the calc and see what happens at any point in the loop and still have the original observation data logged for QA.

Least squares distribution of error. TheoLt through its partnership with kubit uses a powerful network adjustment algorithm. By moving away from Bowditch (sob!) towards a distributed error network the traverse can be extended to include resections.

TheoLt orientation procedure builds the network data table which shows how good the shots are, how many shots there are in the set and allows you to include or exclude a shot from the computation. I can get reports out on the condition of the network when I run the calc to test the impact of the include/exclude options I use:

Let’s take a look at the report:

TheoLt NetAdjust does traversing nicely but there are drawbacks, its not something I would expect the whole survey world to use. It’s dependent on a PC so its not going to be what I would use on a windswept fellside in driving rain. For me it’s a godsend simply because I can get good control without fuss and move on to what I want to do…draw!

Control networks are essential for a complex building plan. The exterior can often be controlled by a fairly traditional loop with some fun & games to accept GPS points. Once tied to the exterior loop the interior can usually be fixed by resection throughout.

There is always something that gets in the way!

A control network needs to provide points with a higher order of precision than simple polar observations. Easy to say, a fiddle to do, but a whole lot simpler with TheoLt!

www.theolt.com

More on the TheoLt story here:

http://www.caduser.com/reviews/reviews.asp?a_id=187

TheoLt: The CAD in CADW Surveys!

This week I spent two wonderful days as a guest of CADW working at Chepstow Castle.

CADW site listing and…History of the Castle

The castle is a gem, and it was a privilege to be shown some of its secrets by the conservation experts I was working with. We had awful weather but we didn’t mind, as working together, we were able to get a good plan of the 2nd floor of Martens tower and, for me at any rate,  this is the finest kind of work there is!

The Architects Dept. of the national heritage body for Wales need surveys for site conservation and development. Following a demonstration at the Digital Past event in Cardiff earlier in the year the Architectural Technicians Team bought TheoLt Pro to work with their Leica 1200 series instrument.

I agreed to supply 2 days of  ‘on demand’ training for Paul Hayes, Michael Hopkins and Tony Kinson who handle a variety of challenging projects which need critical survey information in real-time.

Survey is a key tool in site development of any kind, and heritage sites have very specific survey needs. The CADW team get most of their survey done by contract survey companies working under a framework agreement, but there is a constant need to get small tricky areas surveyed quickly to kick off a design scheme for new visitor accommodation such as ticket offices, access pathways and the like.  Surveys need to be quick, in CAD, and annotated with levels in plan section and elevation.

The training session began with a quick assessment of training need and moved straight into practical procedures: getting a quick survey started using default orientation is a very useful way of getting the most out of limited site time, and the TheoLt ‘Default orientation’ option proved the point- once the kit is set up you can begin collecting precise 3D wire frame in minutes!

Its worth remembering TheoLt was designed for just this kind of scenario; a CAD plot of a single wall profile can make all the difference in project design and the software puts the absolute minimum between the surveyor and the CAD drawing. The CADW team are focused on solving project information needs and were impressed with the direct to DWG approach.

Working as training and support for Latimer CAD I find building a good relationship with TheoLt users rewarding and fun: its great to know CADW are able to get the most out of their 1200 now they can work with TheoLt!

We quickly worked through our training agenda:

  • Quick start
  • Preparing plans
  • the 3 methods of orientation
  • using UCS for 3d views
  • handling linetypes and line typescale
  • checking precision
  • level annotation using attributed blocks
  • toolbar customisation
  • working with AutoCAD alternatives- BricsCAD
  • TPS 1200 interface.  the pdf on this is here

Getting to know the ‘most wanted’ AutoCAD commands in surveying turned out to take up almost as much of our time as getting to know the TheoLt interface, this was no surprise to me as I know when TheoLt is used well it’s virtually invisible, making the job an AutoCAD one rather than a surveying one!

CADW need sections, levels and plans of the ‘hard to reach’ parts of their monuments and sites and this is just where the flexibility of TheoLt is an asset to the CADW team. At the very beginning of our session I was told the frequency of survey activity in the workgroup was very variable and they needed a method that is simple enough to pick up months after last use.  By the time we packed up at the close of the session I was cheered to hear user comment like ‘this is so much better that what we did before; you can see your mistakes as you make them!’

Driving home along the banks of the River Severn I was reminded of my first days doing CAD surveys and how often I would get stuck and have no help at all ( it was ‘PenMap’ in those days) and I look forward to the CADW teams first site survey with TheoLt because, of course, I’ll be there if needed to build the skills required; I have opened the door of opportunity for these surveyors and I am proud to have been invited to do so!