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1、SDRC/Imageware Class A Training - Basic Page 1 of 92 SDRC 2000 Basic Class A Training Methods 1 Methods Model Preparation SDRC/Imageware Class A Training - Basic Page 2 of 92 SDRC 2000 Introduction. Having covered the basic command used in this stage of the overall process we will now apply them to
2、a somewhat more realistic example. The following pages are intended to guide you through what to do if you cannot remember HOW to do one of the operations requested refer back to the Procedures manual for a more detailed explanation of how to complete the step. If you get really stuck first go back
3、to the procedure example and do it again, if this does not solve the problem then ask your instructor for assistance. During this process it is also a useful discipline to get into the habit of looking at the on-line help & documentation often you will find the answers/guidance you need in these tex
4、ts and of course you have access to them on any machine running Surfacer! SDRC/Imageware Class A Training - Basic Page 3 of 92 SDRC 2000 Methods 1 Model Preparation Stage 1Open the Raw data Model Open the file m1_raw_data.imw. The model should look like this:- The data has been gathered using a came
5、ra system. The part was placed on a surface plate held down with small amounts of modeling clay along the edges. As a result the lower side edges of the part are a little in-distinct, this is quite typical of real scan data. The part was aligned in the Z direction by being placed flat on the surface
6、 plate as a result the z datum comes from the plate and should be quite reliable. The y direction was set up correctly but the datum used was the edge of the part the center line actually sits at about y 150.0. The X direction takes its X0 location from the rear edge of the part. The person who carr
7、ied out the scanning also forgot to set the part into the correct direction this part faces the front of the vehicle when it should face the rear. In other words the X value should get larger as we move towards the rear of the vehicle. SDRC/Imageware Class A Training - Basic Page 4 of 92 SDRC 2000 T
8、he first step required of us therefore is to Register the part into its correct place in car coordinates. The required locations are as follows. X rear edge should be at X4000.0 Y center line should be Y0.0 Z lower edge should be Z500.0 The X direction should increase towards the rear of the vehicle
9、. The Values in bold Italic indicate the required values the actuals are shown above. X0.0 X4000.0 Z500.0 Z0.0 X Dir Y150.0 Y0.0 SDRC/Imageware Class A Training - Basic Page 5 of 92 SDRC 2000 Stage 2.Create Reference planes. In the raw data create 3 planes and name them as follows:- X data plane X0
10、plane at the rear of the part Y data planeY150 plane (can be same location as the X plane center) Z data planeZ0 plane (can be centered as above) The extent of each plane should be about 150.0mm in each direction. Use the diagnostics for surface normal direction to make sure the normals point in the
11、 direction you want the model to face after registration. Stage 3.Group the data Create a group containing the planes and the raw point data. Stage 4.Construct Location planes. Construct 3 planes and name them as follows:- X4000x direction plane center 4000,0,500 Y0y direction plane center 4000,0,50
12、0 Z500z direction plane center 4000,0,500 The extent of each plane should be about 200.0 mm in each direction Again check the normal directions of the planes are pointing the way they should (x to the rear , z up etc) SDRC/Imageware Class A Training - Basic Page 6 of 92 SDRC 2000 Stage 5.Register th
13、e data to the correct location. Using stepwise registration register the parts together, remember we have the most confidence in the Z datum, The x was also set reliably , the y may be a little more suspect. The model should start out like this:- SDRC/Imageware Class A Training - Basic Page 7 of 92
14、SDRC 2000 And end up like this:- Ungroup the entities and re-set the home transform for the point cloud when you are sure the registration is correct. You can now delete the reference planes but keep the location planes (x4000, y0, z500) for use later. Save the model at this stage. SDRC/Imageware Cl
15、ass A Training - Basic Page 8 of 92 SDRC 2000 Stage 6.Generate a lower edge section. As we have fairly poor data at the very edge of the part at what was Z0 (now Z500) We will create a section a little higher up and project it to the z500 plane. Create an interactive section through the part as show
16、n here. Using the resulting cloud section project it to the Z500.0 plane. Note that because there is some draft on the side of the part the projected section falls a little in-side what data there is on the z500 plane already we need to take account of this in later operations. SDRC/Imageware Class
17、A Training - Basic Page 9 of 92 SDRC 2000 Stage 7.Cross section the data. The next part of the process is to generate section data through the part this will be our main guide whilst surfacing. Create cloud cross sections as follows:- X direction sections starting at X4000, spacing 50.0mm throughout
18、 the part Y direction sections from x0 spaced at 10.0mm intervals through one side of the part Z direction sections from z500.0 spaced at 10.0mm intervals through the part. Set the section line display to polyline in all cases and set the main cloud display sample to 1 in 10 or hide it completely. T
19、he result should look like this:- SDRC/Imageware Class A Training - Basic Page 10 of 92 SDRC 2000 Stage 8.Polygonize the data. As a final exercise polygonize the data, set the cloud normals to face outside of the cloud needed & examine the form of the part. Surfacing this part will be somewhat diffi
20、cult as you have no reference to the original clay . Instead you will have to rely on the information you can extract from this virtual clay and Surfacers other diagnostic tools! SDRC/Imageware Class A Training - Basic Page 11 of 92 SDRC 2000 Basic Class A Training Methods 2 Methods Patch Creation S
21、DRC/Imageware Class A Training - Basic Page 12 of 92 SDRC 2000 Introduction. This continues the process of building the center console. In the following excersise we will use the procedures learnt in the previous session to create the basic slab surfaces required for the console. Once again refer to
22、 the Surfacer documentation as required together of course with the procedures manual. You will need some of the techniques learnt in the first session. You will also need the completed model from the first methods session, if you do not have this ask the instructor for assisance. SDRC/Imageware Cla
23、ss A Training - Basic Page 13 of 92 SDRC 2000 Methods 2 Basic Surface Creation Stage 1Open the Model from the last methods session Open the file my_stage1_complete.imw. The model should look like this:- Delete the registration planes and make a layer called raw data transfer the dense cloud to this
24、layer (do not make it active) and set the layer to not visible & not pickable. SDRC/Imageware Class A Training - Basic Page 14 of 92 SDRC 2000 Stage 2 - Create reference planes for surface creation. Make reference planes (100x100) at the locations shown these represent the extremities of the part. E
25、dit the plane enter locations so that they fall in sensible positions eg. Y0 instead of y0.001, name the planes according to the convention Y0, z500 etc. SDRC/Imageware Class A Training - Basic Page 15 of 92 SDRC 2000 Stage 3 extract the center line section. From the y scan sections extract just the
26、 Y0 section line and display only this. This section will be used to set up the initial patch. Notice how the amount of information on the screen is kept to a minimum in this way making it easier to avoid mistakes! SDRC/Imageware Class A Training - Basic Page 16 of 92 SDRC 2000 Stage 4 Find curvatur
27、e Break Points Looking in the side view use the un-equal scale command to identify the curvature break points and mark them with a plane. Try to place the planes in an area of fairly constant curvature, just before the curvature starts to change / accelerate. SDRC/Imageware Class A Training - Basic
28、Page 17 of 92 SDRC 2000 Stage 5 Cut new cloud sections. Redisplay the dense cloud (layer settings!) and cut two new sections one for each of the planes created in the previous operation. These will act as a guide for the creation of our first patch. One of the advantages of dense data is that you ar
29、e able to go back to the original scan and cut new sections wherever they are required. This is a major advantage in surface creation removing guess work and speeding up the surface creation process. SDRC/Imageware Class A Training - Basic Page 18 of 92 SDRC 2000 Stage 6 Create the initial patch. Ma
30、ke a 4 point patch as shown do not worry too much about the exact locations of the corners we will fix them later. 1 2 4 3 SDRC/Imageware Class A Training - Basic Page 19 of 92 SDRC 2000 Stage 7 Set the edges of the patch. Show the reference planes again and use the remove twist command to snap the
31、control rows in to the required planes. In the X direction these are the two newly created planes, in y use the y0 plane and the most outboard y plane as shown. Now that the patch edges have been located reliably we can start to edit the patch to shape. SDRC/Imageware Class A Training - Basic Page 2
32、0 of 92 SDRC 2000 Stage 8 editing the patch to shape. The only direction the last operation did not set up exactly was the Z direction. As a result the first editing operation we need to perform is to lift the corners of the patch up in the Z direction only so that we are close to the data. This ope
33、ration must be done before we add interior control points in some cases failure to do so will make editing the rest of the patch un-necessarily difficult. Repeat this procedure for both of the corners that lie on Y0. Move the corner up to the scan SDRC/Imageware Class A Training - Basic Page 21 of 9
34、2 SDRC 2000 Once this has been done displaying only the Y0 scan section go to a side view and use the non-proportional zoom to make the curvature in the y section more visible. Raise the order of the patch by 1 in the x direction only and edit the surface edge to the scan as shown. The time spent ge
35、tting the subtle curvature change captured here will be more than paid back when we come to make transitions into the other surfaces later on. It is always the case with high quality surface modeling that the quality of the blends and fillets that come later is only as good as the underlying surface
36、s upon which they are built. SDRC/Imageware Class A Training - Basic Page 22 of 92 SDRC 2000 Stage 9 make the edge symmetric So far we have set up the center line section correctly the outboard edge we have ignored. To get a good continuity across the center line we will use the make edge curvature
37、symmentric command to snap up the outer edge of points and establish a tangent condition to the center line. Before After Building this type of patch from the center outwards is a very common technique especially in the case of exterior work. SDRC/Imageware Class A Training - Basic Page 23 of 92 SDR
38、C 2000 Stage 10 Matching the X sections Next display only the two new sections that were created in x at the curvature break points & of course our infant patch! Raise the order in the Y direction by 1 as shown here and edit JUST the outer row down in Z until you match the scan as shown. Notice that
39、 in this case the breakpoint on the X sections is accounted for by fitting a simple patch outward from the center line. At this stage do not worry about the middle of the surface the first step is to get the edges right. SDRC/Imageware Class A Training - Basic Page 24 of 92 SDRC 2000 Stage 11 adjust
40、 the interior of the patch. Now we have set the edges up in both directions lets take a look at some more sections and make sure the interior of the patch is the correct shape. Display the X scan sections and make corresponding surface cross section plots on the patch. How close is the middle portio
41、n? If needed move just the middle outer control point to improve the shape. SDRC/Imageware Class A Training - Basic Page 25 of 92 SDRC 2000 Stage 12 check the Quality. Now that the shape looks ok lets run some checks you should be easily within 0.25mm of the point cloud. You should also have smooth
42、well behaved looking curvature plots like below. If you do not edit the surfaces until they are the editing to make changes to these plots is likely to be very small amounts 0.1mm increments is not unusual. SDRC/Imageware Class A Training - Basic Page 26 of 92 SDRC 2000 Once you have checked the cur
43、vature needles , check the highlight lines plot as below. The highlight lines should flow smoothly and evenly without pinching or necking. SDRC/Imageware Class A Training - Basic Page 27 of 92 SDRC 2000 Stage 13 Extend the surface. The surface we created lies close to a region of consistent curvatur
44、e as a result of finding the breakpoints. However we want to blend this surface back later so it may be desirable to extend it just beyond the end of the part. Go back to the side view and Y0 section and extend the surface as shown. This is good practice even if we cut it back again later, building
45、this way allows for design changes like a change to the blend radius at the end of the part. This can save a lot of time if (when) changes are required. SDRC/Imageware Class A Training - Basic Page 28 of 92 SDRC 2000 Stage 14. Check Center line continuity. Next we will use the mirror display and curvature needle plots to check that the flow of curvature across the part looks good (we already k